# COMPLETED.md — ReaSampler landed milestones

Completed milestone entries removed from `PLAN.md`. Each entry preserves its
original Goal, Verify, and checklist points with boxes marked done.

---

## Milestone 0 — Transition scaffold: reaper_mpeview → ReaSampler
**Goal:** Retire the MPE scaffold and stand up the sampler's pure core in its
place, preserving the pure-core / REAPER-shell split.
**Verify:** `cmake -B build -S .` configures clean; `cmake --build build` builds
the renamed extension target and the pure-core test target; `ctest --test-dir
build` is green with the new `bank_model` + `peaks` suites present.

- [x] Delete `src/mpe_model.{h,cpp}` and `src/mpe_view.{h,cpp}`; remove
  `tests/test_mpe_model.cpp`.
- [x] Rename the CMake `project()` and the extension MODULE target from
  `reaper_mpeview` to `reaper_reasampler` (binary `OUTPUT_NAME` likewise);
  update `PREFIX ""` / platform SUFFIX blocks to the new target name.
- [x] Replace the pure `mpe_model` static lib + `mpe_model_tests` executable with
  `bank_model` (pure static lib) + `bank_model_tests`; keep the CTest wiring.
- [x] Repoint `src/main.cpp`: drop the `mpe_view.h` include and all `MpeView_*`
  calls (toggle / IsOpen / OnTimer / Cleanup); stub the extension entry so it
  loads, logs to console, and registers nothing MPE-specific. The
  `command_id` / `gaccel` / `hookcommand` registration *pattern* is preserved for
  reuse (CLAUDE.md §REAPER extension contract) — the MPE action string is removed.
- [x] Choose and record the persistent action-id prefix for the sampler family
  (replaces `CEREBELLUM_MPEVIEW_TOGGLE`); this string is forever-stable once
  shipped (CLAUDE.md §action registration).
- [x] Refresh `README.md` layout/next-step sections to the sampler module set.
  (Landed-work reflection is doc-keeper's; this point exists so the stale MPE
  README does not mislead the first implementer.)

---

## Milestone 1 — bank_model + JSON round-trip (pure)
**Goal:** The `Sample` metadata struct and `BankIndex` (add / remove / query /
tier moves / dedup-by-hash) with JSON serialize/deserialize to `std::string`.
CONTEXT.md §Data model, §Module architecture.
**Verify:** CTest green. Round-trip is lossless (deserialize(serialize(x)) == x)
across all fields; dedup-by-hash and tier filtering asserted; **relative paths
only** invariant enforced at the model boundary (no absolute path accepted/stored).

- [x] Define `Sample` with the full field set (id, display name, relative path,
  source mode, source range in project time + PPQ, track GUID(s), wet/dry,
  channels, SR, length sec + beats, capture tempo, optional key, peak/RMS/LUFS,
  clip flag, tier, content hash, provenance, created ts). CONTEXT.md §Data model.
- [x] `BankIndex`: ordered collection keyed by id; add / remove / query.
- [x] Hash lookup for dedup-by-content-hash.
- [x] Tier model (scratch | archive) + tier-move + tier filtering; scratch marked
  auto-prunable.
- [x] JSON serialize/deserialize to/from `std::string`.
- [x] Tests: full-field round-trip lossless; dedup collapses equal-hash adds;
  tier filter/move correct; relative-path invariant rejects absolute paths;
  empty-index and malformed-JSON edge cases.

---

## Milestone 2 — peaks (pure)
**Goal:** Compute waveform min/max bins from raw PCM, dependency-free (not
REAPER's peak API). CONTEXT.md §Module architecture, §Non-goals.
**Verify:** CTest green. Fed a known signal (full-scale sine, ramp), asserted
min/max envelope per bin matches expected within tolerance; channel count
preserved; bin count honored for arbitrary sample lengths (incl. remainder bin).

- [x] Min/max bin computation from interleaved PCM given a target bin count.
- [x] Multi-channel handling (per-channel envelope; no silent fold).
- [x] Tests: sine envelope ≈ ±amplitude; ramp envelope monotonic; DC/silence →
  zero envelope; short-buffer and non-divisible-length edge cases.

---

## Milestone 3 — Offline capture spike (REAPER shell)
**Goal:** Offline-render the time-selection master mix to a wav in the project
bank folder, add a `Sample`, log it. The render-driving spike. CONTEXT.md
§REAPER API surface (offline render), Build order 3.
**Verify (in DAW):** Render runs via `Main_OnCommand(42230)` ("Render using most
recent settings") — REAPER always shows its offline-render progress window; no
stock/header-documented fully-headless path exists. File lands in the
project-relative bank folder at **32-bit float WAV** at project rate (lossless,
dither-free → enables bit-identical/null-test). A `Sample` is added to the
in-memory `BankIndex`. Non-destructive. Unsaved-project state triggers a
Save-As prompt; capture is refused if the user cancels (no default-location
fallback).
**Bit-identical repeats:** two identical requests produce byte-identical files.
**Exact bounds:** rendered length matches the requested range (no rounding, no
added silence without an explicit tail).

- [x] `ICaptureBackend` interface + `CaptureRequest` (source mode, time range,
  wet/dry, tail, SR/bit-depth/channels, output path). CONTEXT.md §capture.
- [x] `OfflineRenderBackend`: drive `GetSetProjectInfo` render settings +
  `GetSetProjectInfo_String` file/pattern/format; **verify every flag against
  `vendor/reaper-sdk/sdk/reaper_plugin_functions.h`.**
- [x] Resolve the no-dialog render command/flag on the current REAPER build
  (open question) and confirm it runs headless.
- [x] Populate a `Sample` from the finished file; hand to `bank_model`; console-log.
- [x] Verify bit-identical repeats and exact-bounds by hand on a known range.

---

## Milestone 4 — persist (index ↔ project ext state)
**Goal:** Write the `BankIndex` JSON to project ext state, reload on project open;
project-relative path resolution. CONTEXT.md §persist, §Persistence & paths.
**Verify (in DAW):** Index survives Save / Save As / close+reopen; **bank travels
with the .rpp**; **relative paths only** in the persisted index (Save As to a new
folder still resolves the bank).

- [x] `SetProjExtState` / `GetProjExtState` under namespace `"reasampler"`.
- [x] Bank-folder resolution from the current project path
  (`EnumProjects` / `GetProjectPathEx`); store under a project-relative subfolder.
- [x] Reload-on-open; confirm survival across Save / Save As.

**Notes/decisions:**
- Storage: `SetProjExtState` / `GetProjExtState`, namespace `"reasampler"`, keys `bank_index` (serialized JSON) and `project_guid`; relative paths only in the persisted index.
- Project identity: keyed off a **minted GUID** stored in ext state (REAPER exposes no native per-project GUID), not the raw `ReaProject*` — a recycled pointer cannot misread a project switch as a Save-As.
- Save-As: **copy** semantics (Daniel's decision) — the `reasampler_bank/` folder is copied under the new `.rpp`; the old project's bank stays intact. Every ext-state write calls `MarkProjectDirty` so captures/GUID changes flush on the normal save.
- Save-As collision — fixed (DAW-verified): project identity is **GUID-primary** — the stored per-project GUID is the identity of record; a different stored GUID always means a different project (Load its bank), immune to REAPER recycling `ReaProject*` addresses across close/open. The `ReaProject*` pointer is a secondary signal that disambiguates the same-GUID case only: a different object with the same GUID = a Save-As fork (Load + re-GUID to diverge); the same object with the same GUID + a new path = a genuine Save-As in progress (relocate bank). This replaced two earlier iterations: GUID-only (mis-detected forks sharing a copied GUID) and pointer-primary (mis-detected reopen/new-project because it ignored the GUID on address recycling). Non-destructive preserved.

---

## Milestone 5 — bank_panel (docked grid)
**Goal:** Docked LICE-drawn grid: thumbnails (from `peaks`), audition,
multi-select, keyboard navigation. Reuses the docking setup from the retired
`mpe_view.cpp`. CONTEXT.md §bank_panel.
**Verify (in DAW):** Grid docks; thumbnails render from computed peaks; audition
plays selected sample; multi-select + keyboard nav work.

- [x] Docked window + LICE grid render loop.
- [x] Thumbnail draw from `peaks` bins.
- [x] Audition (play selected sample) + stop.
- [x] Multi-select + keyboard navigation.

**Notes/decisions:**
- Thumbnail cache: in-memory recompute keyed by `(sampleId, drawWidth, bankGeneration)`; peak bins are NOT persisted alongside the index. Cache is discarded on bank change and rebuilt on next draw. (Closes the PLAN "thumbnail cache" open question.)
- Audition: stock `PlayPreview` / `StopPreview` API, read-only — display + select + audition only, never inserts into the arrange. Single stop-funnel ensures a leak-free preview lifecycle. Flagged undocumented assumption: `StopPreview` detaches the source before returning; mitigated by the single-funnel design. Escalation path if a runtime pop appears: switch to `StartPreviewFade` + deferred free.

---

## Milestone 6 — insert (placement)
**Goal:** "Insert selected sample at edit cursor" via `InsertMedia`. CONTEXT.md
§insert, Build order 6.
**Verify (in DAW):** Selected sample inserts at the edit cursor wrapped in
`Undo_BeginBlock2` / `Undo_EndBlock2`; conform-to-tempo is an explicit flag —
**no silent time-stretch** when off.

- [x] `InsertMedia(path, mode)` at edit cursor (verify mode bits against SDK).
- [x] Conform-to-project-tempo vs literal as an explicit flag (never silent).
- [x] Undo-block wrapping.

**Notes/decisions:**
- Placement target: inserts the focused bank sample onto the **currently selected track(s) at the edit cursor** (Daniel's directive — not a new track). Uses `InsertMedia` base mode 0; for multiple selected tracks the sample is placed on each at the same cursor position, then the original track selection and edit-cursor position are restored — non-destructive to editing state. The entire operation is one undo block.
- No silent time-stretch: the `&4` stretch-to-time-selection bit is never set; a pure `insert_plan` test asserts this across all mode combinations. Conform-to-project-tempo is an explicit separate action (`&8`), never on the default path.
- Non-destructive to the bank: insert only adds arrange items — no bank/file/ext-state writes.

---

## D1 — view_mode_model (pure)
**Goal:** REAPER-free mode registry + membership index + folder-tree-aware
visibility derivation + parking/restore planner + JSON round-trip. The heart of the
phase; mirror of `bank_model`. CONTEXT.md §Design View (Module architecture — pure).
**Verify:** CTest green. N-mode model (not a boolean); Arrange + Design seeded.
Restore-planner round-trip (snapshot → park → restore) returns every driven flag to
its captured value. Parent-derivation correct against a supplied folder tree.
JSON round-trip lossless across modes + membership + show-both + snapshots + active
mode.

- [x] Mode registry: ordered (id, display name, ordinal); Arrange + Design seeded;
  add/query more modes (prove N-mode, not binary).
- [x] Membership index: `GUID → { mode ids }` + per-track show-both flag;
  add / remove / retag / query; untagged = Arrange.
- [x] Folder-tree-aware visibility derivation: given a supplied parent↔child tree +
  active mode, compute the visible set (active leaves, derived-visible parents,
  show-both leaves, master always in).
- [x] Parking/restore planner: emit exact (track, flag, value) op-lists for park and
  restore from active mode + snapshot record.
- [x] JSON round-trip: modes + membership + show-both + snapshots + active mode.
- [x] Tests: N-mode add/query; parent follows tagged leaf (multi-mode parent);
  restore-round-trip returns snapshot values (never hardcoded "on"); show-both leaf
  never parked; unknown/stale GUID tolerated; JSON lossless.

---

## D2 — view shell (apply flags in the DAW)
**Goal:** Read the folder tree and drive REAPER flags per the planner.
CONTEXT.md §Design View (view shell, REAPER API surface).
**Verify (in DAW):** Toggling active mode hides + parks inactive leaves
(`B_SHOWINTCP`/`B_SHOWINMIXER`/`B_MAINSEND`/`I_FXEN` + per-FX offline) and restores
active ones from snapshot. **Master untouched. `B_MUTE`/`I_SOLO` untouched.**
Untagged tracks untouched. Parents follow their tagged descendants.

- [x] Build parent↔child tree from `I_FOLDERDEPTH`; feed to `view_mode_model`.
- [x] Snapshot prior flag values (`GetMediaTrackInfo_Value`) before parking.
- [x] Apply park/restore ops (`SetMediaTrackInfo_Value` for the four flags;
  `TrackFX_GetCount` + per-FX `TrackFX_SetOffline`). Verify flag names/signatures.
- [x] GUID resolution: `GetTrackGUID` / `guidToString` / `stringToGuid` (never index).
- [x] Review gate: no path touches master visibility or `B_MUTE`/`I_SOLO`, or any
  untagged track's owned flags.

---

## D3 — persist slice (view state ↔ project ext state)
**Goal:** Serialize the view section into the `"reasampler"` namespace alongside the
bank; reapply the active mode on project open. CONTEXT.md §Design View (persist).
**Verify (in DAW):** Membership + active mode + snapshots survive Save / Save As /
close+reopen; on open, the active mode's visibility + processing is reapplied.
Saved-while-parked project restores parked tracks from persisted snapshots (not to a
guessed "on").

- [x] Serialize/deserialize the view section under `"reasampler"` (shared blob,
  distinct section from the bank index).
- [x] Reapply active mode on project open (rebuild tree, run the planner).
- [x] Confirm survival across Save / Save As; snapshot durability across
  save-while-parked.

---

## D4 — actions
**Goal:** Bindable action set for the mode workflow. CONTEXT.md §Design View
(actions). **Verify (in DAW):** Each action registered (bindable in Actions list);
toggle + mode-jumps MIDI-bindable; tag/untag acts on the current track selection.

- [x] Toggle active mode (cycle; extensible to cycle-all for >2 modes).
- [x] Activate mode: Arrange / Activate mode: Design (direct jumps).
- [x] Tag selected tracks → Design / → Arrange; Untag selected (= → Arrange).
- [x] Show-both for selected tracks (toggle).
- [x] Register each (`command_id`/`gaccel`/`hookcommand`); toggle + jumps MIDI-bindable.

**Notes/decisions:**
- New `src/actions.{h,cpp}` — the Design View action family registered via the
  `command_id`/`gaccel`/`hookcommand` contract in `main.cpp`; MIDI-bindable.
- New `src/track_guid.{h,cpp}` — shared `MediaTrack*` → canonical GUID-string
  formatter; used by both the view shell and the actions layer (single source of
  truth for membership keys).
- Wiring: actions drive the D2 view shell and D3-persisted model; saved active mode
  is reapplied on project load via a load-signal seam in `persist` (`loadFromProject`
  raises it; `main.cpp`'s timer drains it) — `persist` stays model-only.
- A pure `nextModeId` free function added to `view_mode_model` (the N-mode cycle
  decision behind "toggle"), unit-tested in the existing `view_mode_model_tests`.

---

## D5 — in-window toggle affordance (UI)
**Goal:** The segmented mode switch in the ReaSampler / bank_panel window header.
CONTEXT.md §Design View (UI). **Verify (in DAW):** Segmented control shows current
mode (lit segment), one click flips modes via the D4 toggle action, per-mode
membership count visible, offlined-FX caveat surfaced as a tooltip.

- [x] Segmented mode switch `[ Arrange | Design ]` in the window header; active lit.
- [x] Wire the switch to the toggle/activate actions from D4.
- [x] Per-mode membership count display.
- [x] Offlined-FX re-init caveat as a tooltip on the switch.

**Notes/decisions:**
- New PURE module `src/mode_switch.{h,cpp}` — REAPER-free layout math for the
  Design View mode switch: divides a header rectangle into N equal segments (one per
  registered mode) and hit-tests a point to a segment. Unit-tested via a new
  `mode_switch_tests` CTest target. Mirror of `bank_grid`.
- `src/bank_panel.cpp` — segmented `[ Arrange | Design ]` control drawn in the panel
  header (one lit segment per registered mode, click activates that mode via
  `view::applyMode`), with the grid offset below the header.

---

## D2-W1 — view_mode_model lane extension (pure)
**Goal:** Extend D1's pure planner to item level for the two-canvas sub-phase:
lane↔mode mapping, a managed-vs-manual lane-ownership index, managed-only item-lane
ops in the toggle planner, the "which lanes may this toggle touch" query, the
auto-tag decision (manual-lane items exempt; pre-existing ⇒ Arrange), and JSON
round-trip of the lane index. REAPER-free, unit-tested; mirror of D1. CONTEXT.md
§Two-canvas sub-phase (Module architecture — pure).
**Verify:** CTest green; D1 behavior and tests unchanged.

- [x] Lane↔mode mapping: which lane maps to which mode, which `C_LANEPLAYS` value
  per mode.
- [x] Lane-ownership index: per (track GUID, lane) managed-which-mode vs manual;
  managed-only item-lane op family alongside the existing track-flag op family.
- [x] "Which lanes may this toggle touch" query (managed only) — planner emits lane
  ops for managed lanes only, never for manual lanes.
- [x] Auto-tag decision (pure): new track/item GUIDs + active mode ⇒ membership
  writes; manual-lane items exempt; pre-existing ⇒ Arrange.
- [x] JSON round-trip of the lane-ownership index.
- [x] Tests: managed/manual partition; toggle-touches-managed-only; auto-tag
  exemption for manual-lane items; JSON lossless; D1 behavior/tests unchanged.

---

## D2-W2 — shell: lane application + new-content detection
**Goal:** The view shell applies the planner's managed-lane ops in the DAW and the
bank_panel timer detects new content and auto-tags it to the active mode. Resolves
the two flagged implementation design points (I_FIXEDLANE reorder/renumber
fragility; the auto-tag / manual-lane detection heuristic). See CONTEXT.md
§Two-canvas sub-phase (Module architecture — shell; New-content detection).
**Verify (in DAW):** Toggling a mode shows + plays only the active mode's managed
lane, hides + silences the inactive-mode lane, and **never touches a manual lane**
(its `C_LANEPLAYS` stays exactly as the user set it); new content created while a
mode is active is tagged to that mode; pre-existing content stays Arrange (no
mass-tag on the first poll after open).
**Depends on:** D2-W1.

- [x] Apply managed-lane ops in the view shell (`I_FREEMODE`/`I_FIXEDLANE`/
  `C_LANEPLAYS`/`B_FIXEDLANE_HIDDEN` via the item/track info setters;
  `UpdateTimeline()` after `I_FREEMODE`); **managed lanes only, never manual**.
  Verify every flag name/signature against the SDK header.
- [x] New-content detection on the bank_panel timer: diff the live track/item GUID
  set against the previous poll; tag any GUID new since the last poll to the
  then-active mode, with a **first-poll-after-open guard** (pre-existing ⇒ Arrange,
  no mass-tag) and the **manual-lane exemption** (items in a manual lane not tagged).
- [x] Resolve the manual-lane detection heuristic (which new items are exempt) and
  the `I_FIXEDLANE` lane-identity fragility (index survival across lane
  reorder/renumber/deletion) — the two open design points from CONTEXT.md.
- [x] D2-W1 review polish: document the one-managed-lane-per-mode-per-track
  exclusivity assumption in `laneModeState` (comment / debug-guard); clarify the
  `serialize()` one-line style note; optional round-trip tests for the
  last-writer-wins lane-replace contract.

**Notes/decisions:**
- Two new pure modules added with unit tests: `guid_diff` (diffs live track/item
  GUID sets between polls) and `lane_keys` (manages lane identity via durable
  `P_LANENAME` rather than the renumber-prone `I_FIXEDLANE` ordinal, reconciled each
  apply — the resolution to the lane-identity fragility design point). CTest green.
- **Manual-lane protection:** a single pure predicate `isOnManualLane` is the
  exclusive gate; manual lanes — including REAPER's default unnamed fixed lanes —
  are provably never driven or auto-tagged.
- **Track-level auto-tag and park behavior is live.** Item-lane show/hide is
  correctly structured but is a provable no-op on real projects until D2-W3 mints
  the `reasampler:`-prefixed named lanes. End-to-end DAW verification of item-lane
  show/hide is sequenced after D2-W3 for this reason.
- W1 review polish was folded in during this wave.

---

## Milestone 7 — capture action family
**Goal:** Bindable capture actions for master / selected tracks / selected items /
razor area, each with wet-dry + tail options. CONTEXT.md §actions, Build order 7.
**Verify (in DAW):** Each action registered (bindable in Actions list), routes to
the offline backend, and honors wet/dry + tail. **Load-bearing principle:** none
auto-inserts into the arrange.

- [x] Source resolvers: master mix, selected tracks, selected items, razor area
  (`GetSet_LoopTimeRange`, `P_RAZOREDITS`, `CountSelectedMediaItems`, etc.).
- [x] Register each as a bindable action (`command_id`/`gaccel`/`hookcommand`).
- [x] Wet-dry + tail options per action.
- [x] Review gate: confirm no capture path touches the timeline.

**Notes/decisions:**
- Four **wet** bindable capture actions — master mix, selected tracks, selected items, razor area — registered under the `CEREBELLUM_REASAMPLER_CAPTURE_*` command-id prefix. Each routes to `OfflineRenderBackend` (RENDER_* snapshot/restore, dither/normalize off, 32-bit float), produces a `Sample`, adds it to the bank, persists, and calls `MarkProjectDirty`. The M3 spike action was retired.
- **Wet-only decision (Daniel):** REAPER offline render has no true pre-FX "dry" bit — the only wet/dry-adjacent lever (`&8192` pre-fader stems) is post-FX. Approximate-dry action variants were removed rather than ship a "dry" that isn't. `CaptureRequest.wetDry` is retained as the seam for true dry (M10).
- Pure `render_settings` module maps source mode → RENDER_SETTINGS bits and parses `P_RAZOREDITS` (union of track-audio areas), unit-tested. No capture path inserts into the arrange (load-bearing gate); non-destructive (selection/razor read-only).

**Superseded / reworked (post-landing):**
- The four wet source-mode actions (master/tracks/items/razor) were replaced by **three FX-scope actions** — `capture item`, `capture track`, `capture master` — with range (razor-else-time-selection) inferred orthogonally. This fixed the defect where item captures were rendered through the parent FX chain.
- **FX-scope semantics (initial rework):** item = item/take FX only; track = item FX + the selected track's own track FX; master = full chain. For item/track, the out-of-scope chain (ancestors + master, plus the item's own track for item scope) is neutralized during the render.
- **Master scope subsequently removed:** capture is now **two scopes — item and track only**. `CAPTURE_MASTER` and `CAPTURE_MASTER_REALTIME` are retired (to capture the master, render a track instead). The master track is still neutralized as out-of-scope chain for both item and track captures; it is a bypass target, not a capture scope. The realtime backend taps the selected track (track scope only; item realtime deferred).
- **`FxBypassGuard` (RAII):** snapshot → neutralize (FX bypassed via `I_FXEN`; gain zeroed via `D_VOL`; pan/width/pan-law/mode set to unity via `D_PAN`/`D_WIDTH`/`D_PANLAW`/`I_PANMODE`) → render → restore. Non-destructive. This guard is the reusable mechanism M8 (realtime backend) and M10 (null-test / true dry) build on.

---

## Milestone 8 — RealtimeRecordBackend
**Goal:** Realtime record behind the same `ICaptureBackend`, producing identical
bank entries. CONTEXT.md §capture (realtime), §Precision invariants.
**Verify (in DAW):** Hidden temp track taps each selected track's own post-fader
output via a `CreateTrackSend`; recorded file moves into the bank; **non-destructive**
— temp track (and its sends) removed cleanly, every snapshotted track arm, time
selection, and edit cursor restored unchanged on every terminal path.

- [x] Track-scope tap: a `CreateTrackSend(source, temp)` from each selected track
  into a hidden temp track (`B_MAINSEND=0`, hidden from TCP/mixer). The temp records
  its own post-fader output — capturing each source track's output **after its own FX
  and fader, before the parent/folder/master sums it** — chain-independent by
  construction. No `FxBypassGuard` needed or used. Multiple selected tracks sum in the
  temp track (matching offline track scope). Item realtime deferred (`UnsupportedMode`).
  No track selected → refused.
- [x] Timer-driven async state machine (`begin`/`tick`/`abort` driven by `OnTimer`,
  non-blocking — REAPER's UI stays responsive across the record). `begin()` validates,
  snapshots all state, creates the temp track, routes the tap, arms, calls
  `CSurf_OnRecord`, and **returns immediately**. `tick()` (called from `OnTimer`)
  reads the transport via `GetPlayStateEx`/`GetPlayPositionEx` scoped to the record's
  own `ReaProject*` (project-switch safe), advances the pure `advanceRecordPhase`
  state machine, and on a terminal verdict stops + finalizes/restores. `abort()` is
  the force-terminate path for shutdown and project switch.
- [x] `RealtimeCaptureState` snapshot + idempotent restore: snapshots cursor,
  time selection, and every other track's `I_RECARM`; restore() is latched
  (`restored_` flag) and safe to call from whichever terminal path fires first.
  Terminal paths: normal completion, manual stop, error, second-capture reject,
  project switch (project-scoped `OnStopButtonEx(proj_)`, never the global
  `CSurf_OnStop`), **project close** (guarded by `ValidatePtr2(nullptr, proj_,
  "ReaProject*")` — a closed project calls `dropWithoutRestore()` rather than
  touching freed pointers), and extension unload.
- [x] `Finalizing` flush-wait before file move: after the transport stops,
  `tick()` waits for the recorded file size to be positive and stable across a tick
  before calling `finalizeRecording` (file is no longer being written by REAPER's
  audio thread). A wall-clock ceiling (steady-clock, independent of the play cursor)
  bounds both the total record duration and the flush wait separately.
- [x] Move recorded source into bank: `recordedFilePath` discovers the take's source
  file from the temp track's first media item; `finalizeRecording` moves it into the
  bank folder (cross-volume fallback: copy+remove); populates a `Sample` via
  `sampleFromRecordedCapture`; clean teardown via `restore()` deletes the temp track
  (which REAPER uses to automatically remove every send routed into it).
- [x] Dialog-free; realtime is inherently non-deterministic (documented, not asserted
  bit-identical); saved-project gate (refuses + prompts Save-As if unsaved, matching
  offline). Bindable **cancel** action registered. Master scope removed entirely —
  to capture the master, render a track.

**Notes/decisions:**
- **Track scope only this increment.** Item realtime is deferred: item scope needs
  per-item take isolation on top of the track-output tap — a separate increment.
- **TAP vs. FxBypassGuard.** The `CreateTrackSend` defaults to post-fader
  (`I_SENDMODE=0`) with full-stereo (`I_SRCCHAN` default): post-fader taps the source
  track after its own FX and fader/pan, before the parent sums it. The parent chain
  downstream of that branch is not in the tapped path at all — so there is nothing to
  neutralize and `FxBypassGuard` (which mutates the live chain, altering the user's
  monitoring) is deliberately not used. This also fixed the earlier silent-file bug
  from the spike, which sent FROM the master INTO a temp track (a feedback loop REAPER
  refuses, recording silence). A regular track→track send has no feedback.
- **Project-close guard.** `abort()` gates every REAPER call on
  `ValidatePtr2(nullptr, proj_, "ReaProject*")`. A closed project already reclaimed
  its temp track, arms, and transport — `dropWithoutRestore()` latches `restored_`
  and clears `temp_` / `armSnaps_` without touching any REAPER pointer.
- **No undo block.** The transient mutations (temp track, sends, arm, transport) are
  fully reversed by `restore()`; surfacing them as an undo point would pollute the
  user's history with an internal scaffold they cannot meaningfully undo.

---

## T1 — offline tail: auto (default) + manual override
**Goal:** Preserve decay tails on offline captures. **Auto**: render an 8 s-capped
tail, then auto-trim trailing silence to -72 dB via a **surgical** `RENDER_NORMALIZE`
(only the trim-end bit, `32768`) + a derived `RENDER_TRIMEND` amplitude ratio.
**Manual**: a fixed tail length clamped to the 8 s cap, no trim. **None** (default):
exact bounds, byte-identical to the pre-tail capture. See
`docs/product/capture-tail.md` §The offline path.
**Verify (in DAW):** A range ending mid-reverb + Auto tail ends at the -72 dB decay
point (not a hard 8 s, not the range end); a non-decaying signal caps at range + 8 s;
**two identical Auto requests are byte-identical** (deterministic trim); a
TailMode::None capture is byte-identical to the pre-tail exact-bounds capture;
Manual(N ms) yields range + N ms untrimmed, with N clamped to 8000;
`ScopedRenderSettings` restores `RENDER_NORMALIZE` and every touched setting on every
path.

- [x] Pure layer (`render_settings.{h,cpp}`): named constants `kAutoTrimThresholdDb`
  (-72) + derived `RENDER_TRIMEND` amplitude ratio via `autoTrimEndRatio()` (≈
  0.00025119 for -72 dB, computed as `10^(dB/20)` — `std::pow` is not `constexpr`
  before C++26 so this is a function, not a constant), `kMaxTailSeconds`/`kMaxTailMs`
  (8 s); `TailMode { None, Auto, Manual }` enum; `TailRenderSettings` struct
  (tailFlag/tailMs/normalize/trimEnd); `tailRenderSettingsFor(mode, manualTailMs)`
  mapping (None = kTailFlagNone + kNormalizeDisableAll; Auto = kTailFlagCustomBounds
  + kMaxTailMs + kNormalizeTrimEnd (32768) + autoTrimEndRatio(); Manual =
  kTailFlagCustomBounds + clamped ms + kNormalizeDisableAll); unit-tested.
- [x] Wire the mapping into `OfflineRenderBackend` (`capture.cpp`): drives tail +
  surgical-normalize (Auto) / disable-all (Manual/None) via `GetSetProjectInfo`;
  `ScopedRenderSettings` snapshots and restores `RENDER_TRIMEND` alongside the
  existing `RENDER_*` set. `RENDER_TAILFLAG = kTailFlagCustomBounds` (1) for Auto
  and Manual — custom bounds is the always-applicable tail bit for offline captures.
- [x] `CaptureRequest` three-state tail contract (None/Auto/Manual(ms)); default
  None (exact bounds, null-test-safe). The earlier `renderTail` bool/`tailMs` pair
  was superseded.
- [x] Exposure: a **docked-panel footer toggle** (label "Tail: Off" / "Tail: Auto" /
  "Tail: Manual", cycles on click via `cycleTailMode`) in `bank_panel.cpp`, backed
  by the pure `tail_control` module (`TailSetting`, `cycleTailMode`,
  `clampManualMs`, `tailToggleLabel` — unit-tested). Default `TailMode::None`.
  `CAPTURE_ITEM` and `CAPTURE_TRACK` read the panel setting at fire time — **no
  per-action tail variants shipped** (the "…with tail" variants were dropped in
  favour of the toggle; null-test/verify captures use None explicitly).
- [x] DAW-confirm: `RENDER_TRIMEND` amplitude curve (0.00025119 ≈ -72 dB); trim-end-only
  normalize (32768) does not engage fades/normalize/pad; trim never eats pre-`ENDPOS`
  body. (See spec §Open questions / DAW-confirm.)

**Notes/decisions:**
- **Surgical normalize.** `kNormalizeTrimEnd = 32768` sets only the trim-ending-silence
  bit; every other postprocessing bit is clear. A fixed-threshold trailing-silence trim
  scales and fades nothing, so two identical Auto requests trim at the identical sample
  → bit-identical repeats hold (spec §surgical normalize).
- **`kNormalizeDisableAll = (4 << 16) = 262144`.** Used for None and Manual — the
  same disable-all value the pre-tail exact-bounds capture used.
- **`tail_control` pure module** (`src/tail_control.{h,cpp}`): REAPER-free logic for
  the panel toggle. `kDefaultManualTailMs = 2000.0` (2 s). Fine-adjust UI (scroll-wheel
  in 250 ms steps) and per-project persistence landed as T1-followons (see below).
- **Follow-ons resolved:** Manual fine-adjust UI and per-project persistence of the
  toggle landed as T1-followons. T2 realtime tail landed separately.

---

## T2 — realtime tail (follow-on to T1)
**Goal:** The parallel tail path for the M8 realtime backend, which does not drive
`RENDER_*`: record an 8 s-capped tail window past the range end, then **trim in a
PCM decay-scan** to the -72 dB point (Manual = record fixed tail, skip the scan).
See `docs/product/capture-tail.md` §The realtime path.
**Verify (in DAW):** A realtime Auto capture of a decaying source records ≥ the range
then trims at the -72 dB decay point (± inherent realtime tolerance); realtime tail is
**not** asserted bit-identical (documented non-determinism).
**Depends on:** T1, M8.

- [x] Record `[start, end + clamp(tail, 8 s)]` (extend the record time selection in
  `capture_realtime.cpp`); Manual skips the scan, Auto proceeds to it.
- [x] Pure decay-scan helper alongside `peaks`: `lastFrameAboveThreshold(interleaved,
  channels, frames, linearThreshold) -> frameIndex` (backward scan, per-frame max-abs
  across channels, no fold); unit-tested with a synthetic decaying ramp. (Spec §realtime
  path option (a) — recommended over bending `computeEnvelope`.)
- [x] Realtime shell: read the recorded wav PCM into a float buffer, find the trim
  frame, rewrite the file truncated (new I/O the backend does not do today).

**Notes/decisions:**
- New pure module `wav_trim` (`src/wav_trim.{h,cpp}`): 32-bit-float WAV parse + header-aware
  truncate plan (RIFF/data size rewrite). Rejects WAVE_FORMAT_EXTENSIBLE with non-float
  SubFormat GUID. Depends on `peaks` for the `AudioSample` float alias. Unit-tested via a
  new `wav_trim_tests` CTest target.
- `peaks` gained `lastFrameAboveThreshold` (backward PCM scan, per-frame max-abs across
  channels, no fold) for the Auto decay scan.
- **Auto/Manual/Off semantics.** Auto: records `[start, end + 8 s cap]`, scans backward
  for the last frame above -72 dBFS, truncates the WAV header-aware at that frame. Manual:
  records `[start, end + fixed tail]`, skips the scan. Off: byte-identical to the pre-tail
  exact-bounds capture.
- **Realtime tail is non-deterministic by design** (inherent to the realtime backend).
  Bit-identical repeats are not asserted for the realtime path; this is documented, not a defect.

---

## T1-followons — Manual fine-adjust UI + per-project tail persistence
**Goal:** Close the two follow-ons deferred at T1 landing: (1) scroll-wheel fine-adjust
of the Manual tail length in the panel footer; (2) the tail setting (mode + Manual length)
persists per-project inside the `.rpp` rather than resetting on extension unload.
**Verify (in DAW):** Scroll-wheel over the footer adjusts Manual length in 250 ms steps,
clamped 0–8 s; the label reads "Tail: Manual X.Xs" (one decimal) in Manual mode; footer
click still cycles Off → Auto → Manual. The tail setting survives Save / close+reopen;
projects with no stored key fall back to Off / 2 s.
**Depends on:** T1.

- [x] `adjustManualMs(current, notches, stepMs)` pure helper in `tail_control` (per-notch
  ±`kManualStepMs` = 250 ms, clamped [0, `kMaxTailMs`]); unit-tested.
- [x] `tailToggleLabel` updated: Manual mode appends the clamped length in seconds to one
  decimal, e.g. `"Tail: Manual 2.0s"`; unit-tested at boundary lengths.
- [x] Panel footer scroll-wheel handler calls `adjustManualMs` and repaints; click handler
  unchanged (still cycles mode via `cycleTailMode`).
- [x] `serializeTailSetting` / `deserializeTailSetting` pure round-trip (mode + manualMs)
  added to `tail_control`; unit-tested including `std::nullopt` on malformed input.
- [x] `TailSetting tail_` promoted into `ReaSamplerSession` (peer to `bank_` and `view_`);
  `persist` serializes it under the forever-stable key `"tail_setting"` (namespace
  `"reasampler"`) on save and reloads it on project open. Absent key → default Off / 2 s
  (graceful for older/unsaved projects).
- [x] Changing the toggle marks the project dirty and commits the value to ext state;
  `bankPanelTailSetting()` reads through the session (not a panel-local copy).

**Notes/decisions:**
- `kManualStepMs = 250.0` — Daniel-set coarse-but-precise step; one wheel notch = ± 250 ms.
- Label format: `"Tail: Manual 2.0s"` (one decimal, `s` suffix) — format pinned by unit tests.
- Default fallback on absent/malformed key: `TailSetting { TailMode::None, kDefaultManualTailMs }`
  (Off mode, 2 s stored length) — graceful for projects saved before this feature shipped.
- `kProjExtTailKey = "tail_setting"` is forever-stable (changing it would orphan saved choices,
  falling back to the default — graceful but lossy).

---

## D2-W3-A — lane minting + item→lane assignment + persist round-trip
**Goal:** The functional core that makes item-lanes appear: a pure `planLaneMinting`
decision (which tracks hold >1 mode's content, which managed lane each item lands on)
plus the shell apply path in `view.cpp` — enables fixed-lane mode, mints one managed
`reasampler:<mode>`-named lane per involved mode, assigns each item (including
pre-existing) to its mode's lane, and drives per-lane play state, all under one undo
block, triggered off the auto-tag detection tick. Reconciles the lane-ownership index
from durable lane names on project load before active-mode visibility is reapplied.
The lane-ownership index persists inside the `"reasampler"` `view_state` blob (rides
in `ViewModeModel::serialize()` / `deserialize()`).
**Verify:** CTest green (14/14). Pure decision unit-tested in `view_mode_model_tests`.
**DAW verification pending** (Daniel testing on dev): two behaviors are
REAPER-runtime-only — whether lane names stick when written on the same tick the track
flips to fixed-lane mode, and whether the leftover empty default lane 0 is silent.
**Depends on:** D2-W2.

- [x] Pure `planLaneMinting` decision (`view_mode_model.{h,cpp}`): for each reported
  track, collect the distinct modes of managed-eligible items; if < 2 modes, no split
  (D1 whole-track parking still separates stances); if ≥ 2 modes, emit one
  `TrackSplit`, one `LaneMint` per involved mode (durable key = `laneNameForMode(mode)`,
  owned by that mode), and one `LaneAssign` per managed-eligible item — including
  pre-existing items, so a track that just gained a second mode retroactively lanes all
  its content. Manual-lane items (`onManualLane = true`) are exempt at the source:
  never counted, never reassigned, never minted-over.
- [x] Shell apply path `applyMintPlan` in `view.cpp`: enables `I_FREEMODE` = fixed
  lanes, grows `I_NUMFIXEDLANES` (never shrinks — user's manual lanes are never
  deleted), stamps each managed lane's durable name via `P_LANENAME`, records
  ownership in the model (`lanes().setManaged`), assigns each item to its mode's lane
  via `I_FIXEDLANE` resolved from the durable key. Returns `changed` so the Undo block
  is only kept when state actually changed (idempotent re-runs produce no undo point).
- [x] Per-lane play state driven immediately after minting: `planToggle` lane ops
  applied via `applyLaneOps` so the freshly-minted lanes take the correct
  `C_LANEPLAYS` state for the active mode without a full `applyMode` re-run (which
  would re-park/restore whole tracks — not correct for a minting tick).
- [x] `mintManagedLanes` entry point in `view.cpp`: reads live track/item picture via
  `readLaneTracks`, calls `planLaneMinting`, wraps the apply in one Undo block labelled
  `"ReaSampler: separate cross-mode content into lanes"`, calls `UpdateTimeline()` +
  `UpdateArrange()` after a fixed-lane mode change.
- [x] `reconcileManagedLanes` in `view.cpp`: on project load, reads every fixed-lane
  track's `P_LANENAME` values; for each name carrying the managed prefix, records the
  lane as managed-for-its-mode in the ownership index — pure read of REAPER state, no
  lane created or renamed. Called from `main.cpp`'s load path before `applyMode`.
- [x] Lane-ownership index persists via `ViewModeModel::serialize()` /
  `deserialize()` — the `LaneOwnershipIndex` is a member of `ViewModeModel` and
  round-trips inside the `"reasampler"` `view_state` key alongside modes, membership,
  snapshots, and active mode. No new persistence key required.
- [x] Detection tick integration: `mintManagedLanes` is called from the `bank_panel`
  timer after the auto-tag pass, so a newly-tagged multi-mode track is split into lanes
  on the same tick the content is detected.

**Notes/decisions:**
- **Single-mode-track rule:** a track carrying content of only ONE mode is not split —
  D1's whole-track parking continues to separate its stance from the other mode without
  lane overhead. The lane-split only engages when a track genuinely holds ≥ 2 modes'
  content.
- **Manual-lane invariant upheld at the source:** `planLaneMinting` never receives
  manual-lane items as split candidates. The shell's `readLaneTracks` marks items on
  manual lanes `onManualLane = true`; the pure decision skips them entirely. Managed
  lanes are always appended (tail ordinals), never overwriting a user's existing lanes.
- **Idempotency:** re-reporting an already-split track produces the same plan; the
  shell's ensure/assign writes are no-ops when state already matches. The Undo block is
  closed with no label (discarded by REAPER) when the plan is non-empty but every write
  was already satisfied, so no phantom undo points accumulate.
- **Review passed** with no Critical or Major findings.

---

## D2-W3-B — item-level mode actions + W3-A polish
**Goal:** Item-level lane/mode-management actions mirroring the track-level Design
View tag family (bindable in the Actions list), plus the three code-review polish
items carried from D2-W3-A. The persist slice and lane-ownership index round-trip
were completed in D2-W3-A; this wave closes the remaining action surface and
cleans up the implementation.
See CONTEXT.md §Two-canvas sub-phase (Module architecture — persistence).
**Verify (in DAW):** Item mode actions registered and MIDI-bindable in the Actions
list; re-drive mint/apply so each item lands on its mode's managed lane; manual-lane
items exempt; one undo block per action. ctest 14/14 green.
**Depends on:** D2-W3-A.

- [x] "Move selected items → Design" action (`CEREBELLUM_REASAMPLER_VIEW_` family):
  retags selected items' membership to Design mode, re-drives the existing mint/apply
  so each item lands on its mode's managed lane; manual-lane items exempt; one undo
  block.
- [x] "Move selected items → Arrange" action: retags selected items' membership to
  Arrange mode, re-drives mint/apply; manual-lane items exempt; one undo block.
- [x] "Untag selected items" action: removes selected items' membership, re-drives
  mint/apply; manual-lane items exempt; one undo block.
- [x] All three registered (`command_id`/`gaccel`/`hookcommand`); MIDI-bindable.
- [x] W3-A polish — simplified `applyMintPlan`'s redundant `I_NUMFIXEDLANES` re-read:
  single grow-and-track pass removes the second `GetMediaTrackInfo_Value` call inside
  the mint loop.
- [x] W3-A polish — extracted shared item-read seam (`src/item_read.{h,cpp}`):
  removes duplicated `itemGuid`/`itemLaneName` read logic from `view.cpp` and
  `bank_panel.cpp`.
- [x] W3-A polish — added reconcile guard in `reconcileManagedLanes`: skips lanes
  encoding an unregistered mode id (log and skip rather than silently recording an
  orphaned ownership entry).

**Notes/decisions:**
- ctest 14/14 green; review passed with no Critical or Major findings.
- **Panel UI indicator explicitly deferred** (Daniel's decision): a per-track
  lane-split marker has no natural cheap home in the bank panel; the mode switch
  already shows the active mode. Preserved as a deferred/backlog note in PLAN.md
  Phase D2 — not silently dropped.

---

# Phase V — Versioning & release

> **New pillar, own lettered namespace.** Version scheme + beta side-channel.
> Namespaced **`V` (Versioning)** alongside `M`/`D`/`B`/`R` — a distinct concern
> (build identity + channel isolation) that touches CMake, `main.cpp`'s
> forever-stable command-id contract, and the `"reasampler"` ext-state. Product
> framing + full option analysis: `docs/product/versioning-and-release.md`.
> Deploy/CD wiring (two named artifacts per platform) hands off to dev-ops.

## V1/V3 — app_version module: version constant, ext-state stamp, show-version action
**Goal:** Pure `app_version` module — single-source semver from CMake
`REASAMPLER_VERSION "0.9.01"` via `configure_file` → `version_generated.h`;
ext-state writing-version stamp under key `"version"` riding
`saveToActiveProject()`; absent stamp = silent pre-versioning; on-demand
`"ReaSampler: show version"` action (no startup print). New CTest target
`app_version_tests`.
**Verify:** CTest green. Stamp written under `"version"` key on every
`saveToActiveProject()` call. Absent key classifies as `PreVersioning` (silent).
Show-version action fires on demand only.

- [x] `app_version` pure module (`src/app_version.{h,cpp}`): exports the CMake
  version string constant (`appVersion()`), the ext-state stamp value
  (`stampVersion()` — numeric triple only, no channel suffix), `parseVersion`,
  `versionLess`, `classifyWritingVersion` (empty → `PreVersioning`; unparseable →
  `Unknown`; well-formed → `Stamped`). No REAPER types; standard library only.
- [x] `configure_file` wires `REASAMPLER_VERSION` (the one CMake variable) +
  `REASAMPLER_CHANNEL_IS_BETA` into `version_generated.h` in the build tree;
  `app_version` reads from there — one edit re-threads the version string through
  every consumer.
- [x] Writing-version stamp: `persist` calls `SetProjExtState` under
  `kProjExtVersionKey` (`"version"`) with `stampVersion()` inside
  `saveToActiveProject()` on every save. Absent key on load → `PreVersioning`
  (silent; graceful for pre-versioning projects).
- [x] On-demand show-version action (`channelCommandId("SHOW_VERSION")` /
  `channelActionName("show version")`): prints the CMake-sourced `appVersion()`
  string to the console when fired. **No unconditional startup print** (no version
  line added to the extension load message).
- [x] `app_version_tests` CTest target: version parse/compare/classify round-trip;
  `PreVersioning` on empty; `Unknown` on malformed; `Stamped` on well-formed;
  `versionLess` numeric ordering (10 > 9, not lexicographic).

## V4 — beta-in-isolation: fully isolated coexisting binary via compile-time channel flag
**Goal:** Compile-time channel flag `-DREASAMPLER_CHANNEL=beta` → fully isolated
`reaper_reasampler_beta` binary: ext-state namespace `reasampler_beta`, FOREVER-STABLE
command-id prefix `CEREBELLUM_REASAMPLER_BETA_`, `"ReaSampler beta: "` action names,
channel-qualified dock title/ident, `0.9.01-beta` display render, bank-panel footer
version/channel readout. Stable build byte-identical to prior identity.
**Verify (in DAW):** Both binaries load simultaneously in one REAPER via the startup
dlopen. Stable produces no change to any existing action id, ext-state key, or panel
string. Beta reads/writes only `"reasampler_beta"` namespace; its actions carry
`CEREBELLUM_REASAMPLER_BETA_` prefix; its panel shows `0.9.01-beta`. No shared-state
collision path between channels.

- [x] `app_version` extended as the single source of truth for channel identity (V4):
  `channel()`, `isBeta()`, `extStateNamespace()`, `commandIdPrefix()`,
  `actionDisplayPrefix()`, `binaryName()`, `dockTitle()`, `dockIdent()` — all derived
  from the one `REASAMPLER_CHANNEL_IS_BETA` bit. Stable values byte-identical to
  pre-V4 build.
- [x] `channelCommandId(suffix)` / `channelActionName(phrase)` composition helpers:
  every action-registering shell funnels through these so no shell re-implements the
  channel-qualified concatenation. FOREVER-STABLE per channel.
- [x] `configure_file` threads `REASAMPLER_CHANNEL_IS_BETA` (0 for the default build,
  1 for `-DREASAMPLER_CHANNEL=beta`) alongside the version string. Beta binary name,
  namespace, prefix, and display suffix all derive from this one bit.
- [x] All shells (`main.cpp`, `actions.cpp`, `bank_panel.cpp`, `persist.cpp`) updated
  to compose ids/names via `channelCommandId`/`channelActionName` and read
  `extStateNamespace()` — no scattered `#ifdef` forks in the shells.
- [x] Bank-panel footer version/channel readout: displays `appVersion()` (stable:
  `"0.9.01"`, beta: `"0.9.01-beta"`).
- [x] The lane-name `reasampler:` prefix is deliberately NOT channel-qualified (shared
  naming convention; ownership isolated by namespace).
- [x] Stable build: byte-identical to pre-V4 identity on every string that was
  previously shipped.

**Notes/decisions:**
- The stamp value (`stampVersion()`) is the numeric triple only on BOTH channels —
  no `-beta` suffix in the stamp. The channel is carried by the isolated namespace
  (`extStateNamespace()`), not baked into the stamp, so the stamp parses as `Stamped`
  on read-back and stable's stamp is byte-identical regardless of channel build.
- Two permanent commitments accepted: a second forever-stable command-id prefix
  (`CEREBELLUM_REASAMPLER_BETA_`) and a second ext-state namespace
  (`"reasampler_beta"`). Beta keybindings are a distinct forever-family from stable's.
- Isolation semantics (accepted, not a bug): a channel reads/writes only its own
  namespace — a stable project looks empty/default when opened in beta, and vice versa.
  No cross-namespace read, migration, or fallback.
- Deploy implication (dev-ops hand-off): two named artifacts per platform
  (`reaper_reasampler` + `reaper_reasampler_beta`), built by toggling
  `-DREASAMPLER_CHANNEL`.

---

# Phase B — Multi-bank (parallel to the M0–M11 capture roadmap and Phase D)

> **Separate phase namespace.** The M-numbers belong to the capture pillar
> (M0–M11); the D-letters belong to Design View. Multi-bank is a third orthogonal
> pillar — generalizing the single bank into a pool + named banks — so it takes its
> own **lettered** namespace (B1, B2, …). "B" reads for **Banks** and, like Phase D,
> keeps the roadmaps from colliding on numbering: Phase B is not "the twelfth
> capture step," it is a different pillar. Authoritative spec: **CONTEXT.md
> §Multi-bank**. Product framing: `docs/product/multi-bank.md`.

## B1 — bank_book (pure)
**Goal:** REAPER-free bank registry wrapping N `BankIndex` instances: pool seeded +
privileged, create/rename/reorder/delete named banks, active-bank id, move/copy a
sample between banks, JSON round-trip + legacy-migration. The heart of the phase;
mirror of `bank_model` / `view_mode_model`; **`BankIndex` untouched (additive)**.
CONTEXT.md §Multi-bank (Module architecture — pure).
**Verify:** CTest green. Pool always present, un-deletable, un-renamable,
un-evacuable (rules rejected in-model). Active-bank defaults to pool. Move is
index-only (source loses entry, destination gains it) and observes destination
collapse-by-hash; copy leaves source intact. Delete drops member index entries.
Evacuate moves all members to the pool, leaving the bank empty. JSON round-trip
lossless across pool-as-bank-zero + named banks + per-bank indices + ordinals +
active id. Legacy `bank_index` JSON parses into `{ pool }` with zero named banks.

- [x] Bank registry: ordered `{ bank id, display name, ordinal, BankIndex }`; pool
  seeded with fixed id + fixed name; create / rename / reorder / delete named banks
  (delete drops the bank's member index entries).
- [x] Pool-privilege rules enforced in-model: reject delete-pool, reject
  rename-pool, reject evacuate-pool, never allow zero banks.
- [x] Active-bank id (get/set; defaults to pool); resolve active bank's `BankIndex`.
- [x] Move sample between banks (index-only; destination collapse-by-hash observed;
  source entry removed).
- [x] Copy sample between banks (index-only; source entry retained; destination
  collapse-by-hash observed).
- [x] Evacuate bank: move every member to the pool (index-only; destination
  collapse-by-hash observed), leaving the bank empty; pool cannot be evacuated.
- [x] JSON round-trip: pool-as-bank-zero inside the blob + named banks + per-bank
  indices + ordinals + active id.
- [x] Legacy migration: a bare `bank_index` JSON promotes to the pool's index with
  zero named banks (one-way, lossless; blob authoritative thereafter).
- [x] Tests: pool privileges (delete/rename/evacuate rejected); move
  source-loses/dest-gains; copy source-retained; evacuate empties source into pool
  with dest collapse; cross-bank same-hash coexistence; dest collapse on move into a
  bank already holding the hash; JSON lossless; legacy migration.

> **Phase-B-wide undo (fork R-B, settled 2026-07-24 — batched REAPER undo points).**
> Every index verb across B1–B5 (create/rename/reorder/delete-bank, move, copy,
> evacuate, remove) wraps its bank/index mutation in a **batched REAPER undo point**
> (`Undo_BeginBlock` / `Undo_EndBlock`), so one bank operation is one Ctrl-Z. This is
> a cross-cutting decision that retro-touches B1–B4, not a B5-local one; the
> per-verb points above inherit it. **Must-verify before build:** confirm against
> `vendor/reaper-sdk` that `"reasampler"` ext-state mutations participate correctly
> in `Undo_BeginBlock`/`Undo_EndBlock` undo blocks — the whole approach depends on
> it. See CONTEXT.md §Sample removal (Guardrails) + product notes §Fork R-B.

**Notes/decisions (R-B — Phase-B-wide undo, landed):**
- Every bank index verb — bindable action AND panel gesture (menu/drag/Delete key) —
  is one batched REAPER undo point (`Undo_BeginBlock2`/`EndBlock2`,
  `UNDO_STATE_MISCCFG`); ext-state participates in undo via `UNDO_STATE_MISCCFG`
  ("extensions!"), SDK-verified. A `projectconfig` hook
  (`BeginLoadProjectState(isUndo)`) triggers a deferred session reload so Ctrl-Z/redo
  visibly restores book/view/tail/manifest in-session. Rejected/no-op ops open no
  undo point; unsaved-project ops discard the empty block.

---

## B-cap — owned-file manifest seam (capture writes; prune consumes in Phase R)
**Goal:** Capture writes each file it creates into an **owned-file manifest**
persisted in the `"reasampler"` ext-state, so Phase R prune can later distinguish
the bank system's own orphans from hand-dropped files. Consumed only in Phase R
(R1/R2) — landed early here because reconstructing the manifest retroactively is a
backfill cliff (fork R-D, settled 2026-07-24: *defer the feature, design the seam*).
CONTEXT.md §Prune (Settled decisions — orphan attribution) + product notes §Fork R-D.
**Verify:** every file the capture path creates is recorded in the owned-file
manifest; the manifest round-trips through the `"reasampler"` ext-state (Save / Save
As / reopen); relative-paths-only preserved. Prune's consumption of it is Phase R.
**Depends on:** the capture add-path (M7) + persist blob machinery (M4 / B2).

- [x] Capture records each created file into an owned-file manifest (the set of
  files the book has created), persisted in the `"reasampler"` ext-state (sibling
  `owned_files` key — persistence shape resolved at build time: sibling key, not
  folded into the `banks` blob).
- [x] Manifest round-trips: survives Save / Save As / reopen via the M4 blob
  machinery; relative-paths-only. (Consumed by Phase R R1/R2 — not consumed here.)

**Notes/decisions:**
- Pure `owned_manifest` module (`src/owned_manifest.{h,cpp}`): relative paths, dedup,
  JSON round-trip. Deliberately decoupled from `bank_book` — tracks files created, not
  index membership; sample-remove is not manifest-remove. Unit-tested via new
  `owned_manifest_tests` CTest target. Persisted under the `"owned_files"` ext-state
  key. Both capture commit paths (offline + realtime) record created files. Joins the
  undo-reload set.

---

## B2 — persist slice (banks ↔ project ext state)
**Goal:** Serialize the book under the `banks` key in `"reasampler"` alongside the
existing sections, with the pool folded in as bank-zero; migrate a legacy
`bank_index` key into the pool on first load and retire the legacy key; reload-on-open
and Save-As survival via the existing M4 machinery. CONTEXT.md §Multi-bank (persist).
**Verify (in DAW):** Banks + named banks + active bank + all per-bank samples survive
Save / Save As / close+reopen; **relative paths only**; bank travels with the `.rpp`;
a project saved before this phase (legacy `bank_index` only) loads as pool + zero
named banks with no sample loss, and after save carries `banks` with no `bank_index`
written.
**Depends on:** B1. (Persistence-key fork settled — fork 1 (a): pool inside the
`banks` blob, legacy key retired after one-way migration.)

- [x] Serialize/deserialize the book under the `banks` key (pool-as-bank-zero inside
  the blob; distinct section from `view_state`; no `bank_index` key written going
  forward).
- [x] Legacy-migration path on load: absent `banks` + present `bank_index` → promote
  into pool, mint the blob, treat blob as authoritative (legacy key retired).
- [x] Session exposes the book; the active bank's `BankIndex` is the capture add
  target (route the M7 capture family through it — additive to M7, no M7 rewrite).
- [x] Confirm survival across Save / Save As; confirm legacy-project load path.

---

## B3 — actions
**Goal:** Bindable action set for the multi-bank workflow. CONTEXT.md §Multi-bank
(actions). **Verify (in DAW):** Each action registered (bindable in Actions list);
bank-activate + move/copy + evacuate MIDI-bindable; create/rename/delete/evacuate
drive the B1 model via the B2-persisted session.
**Depends on:** B1, B2.

- [x] Create bank / rename bank / delete bank (delete drops member index entries;
  confirm-on-non-empty offered at the UI layer in B4).
- [x] Evacuate bank → pool (move all members back to the pool; refuses on the pool).
- [x] Activate bank (direct-by-id + cycle).
- [x] Move selected samples → bank / copy selected samples → bank (move is default).
- [x] Pool full-height / banks full-height toggles.
- [x] Register each (`command_id`/`gaccel`/`hookcommand`); bank-activate + move/copy
  + evacuate MIDI-bindable.

---

## B4 — bank_panel vertical split (UI)
**Goal:** The vertical-split bank window — pool on top, named-banks tab-page region
below, full-height toggles — extending the M5 docked grid. CONTEXT.md §Multi-bank
(bank_panel). **Verify (in DAW):** Pool grid renders on top; named-banks tab strip
below (empty when no named banks, one tab per named bank); active-bank **unmistakably**
indicated; both full-height toggles collapse the split correctly; sample move/copy
affordance works; non-empty delete confirms and offers evacuate; the Design View mode
switch in the header is unaffected.
**Depends on:** B1, B2, B3. (Tab rendering + move-affordance mechanics — fork 5 —
settled 2026-07-23: LICE-drawn tabs + both move affordances; see Phase B open questions
and product notes → *Fork 5 — settled*.)

- [x] Vertical split: pool grid region (top) + named-banks tab-page region (bottom).
- [x] Named-banks tab strip: **LICE-drawn** (matching the M5 grid + Design View
  segmented switch, not SWELL-native — fork 5a); one tab per named bank; empty state
  when none.
- [x] Tab-strip overflow/scroll affordance (fork 5a): scroll/chevron overflow shipped
  with the strip.
- [x] Pool full-height / banks full-height toggle affordances wired to B3.
- [x] Active-bank indicator — **visually unmistakable** (settled constraint).
- [x] Create / rename / delete / activate / evacuate affordances driving B3 actions.
- [x] Delete confirms on a non-empty bank, naming the evacuate alternative.
- [x] Sample move affordance — **both** (fork 5b): a "move to bank" menu on the current
  selection (bindable front-end for the B3 move action) **and** drag-between-regions.
  Copy is the deliberate secondary act, offered on the menu.
- [x] Drag mis-drop mitigation (fork 5b): clear drop-target highlighting on the
  destination region/tab during a drag.

**Notes/decisions:**
- New pure module `src/tab_strip.{h,cpp}`: named-banks tab-strip geometry (B4) —
  strip rect + N tabs + scroll offset → per-tab rects (overflow-clipped), overflow
  chevron reservation + maxScroll, and point → tab/chevron hit-test. Unit-tested via
  `tab_strip_tests` CTest target. Mirror of `mode_switch`.
- Active-bank indicator placement (the open polish detail from the Phase B open
  questions) was resolved at build time in the panel implementation.
- Post-landing: m11's console-chatter policy applied to Phase B messages (successes
  silent, failures kept).

---

## B5 — sample-remove (the missing sample-level verb)
**Goal:** Drop an individual `Sample`'s index entry from a bank or the pool —
the sample-level companion to move/copy/evacuate/delete-bank. Index-only,
non-destructive to the file; exposes the `BankIndex::remove` primitive that
`bank_model` already has (wires it, does not add it). CONTEXT.md §Sample removal.
Product framing + open forks: `docs/product/removal-and-prune.md` §Sample-remove.
**Verify (in DAW):** Remove drops the selected sample's entry from the target
bank; a same-hash entry in another bank is untouched (no cross-bank dedup);
pool *contents* are removable while pool-container privileges hold; removing the
last index reference to a file leaves that file on disk (orphaned until prune —
never deleted by remove); non-destructive (index + ext-state only, no file, no
timeline item).
**Depends on:** B1, B2, B3 (action set), B4 (panel affordance).

- [x] Surface `BankIndex::remove` through `bank_book`: remove a `Sample` from a
  bank's index; pool contents removable, pool-container privileges unchanged.
- [x] "Remove selected sample(s)" action (`command_id`/`gaccel`/`hookcommand`),
  MIDI-bindable; carries a `scope: this-bank | all-banks` seam (fork R-A, settled
  2026-07-24: **this-bank** is the default and only surfaced affordance; all-banks
  stays a latent seam-only parameter, not shipped).
- [x] `bank_panel` remove affordance on the current selection (reuse M5 selection
  model, as move/copy do).
- [x] Silent remove: no confirm dialog; recoverability via batched REAPER undo
  (R-B) — one Ctrl-Z restores the index entry; files are never deleted by remove.
- [x] Tests: remove drops the target entry; same-hash entry in another bank
  survives; remove-from-pool allowed; last-reference remove leaves an orphan (file
  untouched); non-destructive (no file/timeline mutation).

**Notes/decisions (B5 forks — settled 2026-07-24):**
- **R-A — remove scope.** Settled: **this-bank**. Removes the entry from the bank in
  view only; the `scope: this-bank | all-banks` seam stays in the action signature
  but all-banks is a latent parameter, not a surfaced verb.
- `hashReferencedElsewhere` cross-bank reference query in `bank_book` retained as
  a tested model API for Phase R prune; the remove shells no longer call it.
- Both `bank_panel` context menu ("Remove selected sample(s)") and Delete key
  affordance wired; panel gesture is also one batched undo point (R-B applies).

---

## Milestone 10 — provenance (re-capture from source)
**Goal:** Populate `Sample.provenance` (parent sample id + a capture-recipe
fingerprint) on resample-from-sample, and ship a **"re-capture from source"**
action that regenerates a sample from its recorded source. Reconciled with the
dual-canvas (Phase D2) model. CONTEXT.md §Data model, §capture; product framing +
the settled reconciliation in `docs/product/provenance.md`.
**Verify (in DAW):** A sample resampled from a bank sample carries its parent id +
recipe fingerprint; "re-capture from source" regenerates the file into the bank
(never auto-inserting into the timeline — load-bearing principle); re-capture with
an unchanged source + request is byte-identical to the original (bit-identical
repeats); non-destructive to source items/tracks.

> **Reshaped from the old "provenance + null-test verify" M10.** **Cut (fixed by
> Daniel):** the null-test verification *action* and the true-pre-FX-dry *mechanism*
> the old note required — both dropped, see `docs/product/provenance.md` §What was
> cut. **Kept:** provenance + re-capture. The `Sample.provenance` struct and its JSON
> round-trip **already exist** (M1) — M10 populates and consumes the field, it does
> not add it. Fork picks settled by Daniel (2026-07-23): **P1=a thin fingerprint,
> P2=a bank-only re-capture**; P3/P4 moot under P2=a.

- [x] Populate `Sample.provenance` on resample-from-sample: `parentSampleId` (the
  bank sample the capture derived from) + `fxChainSnapshot` as a **thin capture-recipe
  fingerprint** (scope + source FX-chain identity/hash at capture time — a drift/repro
  fingerprint, NOT a serialized pre-FX-dry chain to restore; P1=a settled).
- [x] "Re-capture from source" action (`RECAPTURE_FROM_SOURCE`, channel-composed):
  regenerate a provenanced sample by re-running its recorded capture request against
  the source's **current** state; update the bank file + Sample in place
  (`BankIndex::updateInPlace` / `BankBook::updateSampleInPlace` — order-preserving,
  id-stable; old file becomes a Phase R orphan). **Bank-only — never inserts/re-places
  into the timeline** (load-bearing principle). Reports drift if the source changed
  since capture.
- [x] Verify: re-capture of an unchanged source is byte-identical to the original
  capture (bit-identical repeats); non-destructive (`FxBypassGuard` snapshot/restore
  as M7); relative-paths-only preserved.

**Dual-canvas reconciliation (settled — `docs/product/provenance.md`):** With
bank-only re-capture (P2=a), provenance is **pure per-sample bank metadata**,
`bank_model` and `view_mode_model` **stay decoupled**, and M10 touches **no** canvas
code. Dual-canvas compliance is satisfied by staying on the right side of the
capture-never-places line — not by any new coupling. Forks P3 (canvas/lane memory in
provenance) and P4 (re-capture auto-tag interaction) were only live under
re-capture-and-replace (P2=b) and are **closed as moot**; if the user manually
re-places a regenerated sample, the existing D2 mode-aware placement rule governs.

**Notes/decisions:**
- Pure `provenance` module: `rsprov1` length-prefixed encoding; captures scope, exact
  range, tail, rate/channels, track GUIDs, order-sensitive FX-chain identity;
  parse/compare for drift detection. NOT a serialized chain to restore.
- `provenance_shell`: FX-chain identity queries via `TrackFX_*` / `TakeFX_*`;
  source-item path collection; parent-detection inputs. Item scope fingerprints take
  FX via `TakeFX_*`; track scope fingerprints track FX. Stamps `Sample.provenance`
  when every resolving source item maps by exact normalized path (case-folded on
  Windows) to exactly one bank sample — ambiguous/mixed cases conservatively record
  nothing.
- **Cut items (correct per spec, not built):** the null-test verification action and
  the pre-FX dry path. Both were explicitly removed at M10 reshaping
  (`docs/product/provenance.md` §What was cut).
- New CTest target `provenance_tests`.

---

## Phase B open questions — all resolved

All five forks settled by Daniel (2026-07-23): persistence key = fold pool into `banks`,
retire legacy key (1a); delete drops members + add evacuate verb (2); move is the
default gesture (3); active-bank/shown-tab distinct with an unmistakable indicator (4);
LICE-drawn tabs + overflow, and both move affordances with drop-highlighting (5).
Active-bank indicator placement (the one residual polish detail) was resolved at
build time. B5 forks R-A and R-B settled 2026-07-24 (see B5 and B1 notes above).
Both in `docs/product/removal-and-prune.md` §Fork R-A / §Fork R-B.

---

# Phase R — Reclaim (file lifecycle: the prune path)

> **New pillar, own lettered namespace.** Prune is the file-lifecycle path the
> capture and multi-bank specs forward-reference throughout ("files persist on disk
> until prune") but that had no phase, module, or point. It is the **only** operation
> in ReaSampler that deletes bytes off disk. Namespaced **`R` (Reclaim)** alongside
> `M`/`D`/`B` because it is a distinct pillar — it serves *every* orphan-producing
> path (delete-bank, sample-remove B5, potentially M10 re-capture), not just
> Multi-bank, and it carries a new risk class (file deletion) with its own
> invariants. Authoritative spec: **CONTEXT.md §Prune — file-lifecycle spec**.
> Product framing + phase-placement justification + forks:
> `docs/product/removal-and-prune.md` §Prune.
>
> **Boundary (load-bearing):** *remove creates orphans; prune reclaims them.* No
> operation other than prune deletes a file; prune deletes only files no index
> references. A bank op that deletes a file is still a bug.
>
> **Depends on:** B1, B2 (needs the multi-bank book to union the referenced-set
> across all banks) and B5 conceptually (sample-remove is a primary orphan-producer,
> so remove-then-prune is the coherent pair — mirror of evacuate-then-delete). Does
> **not** depend on the B3/B4 UI.

## R1 — prune-reconcile core (pure)
**Goal:** REAPER-free, filesystem-free reconciler — given the files present in the
bank folder, the files referenced by the book (unioned across all banks, pool
included), and the **owned-file manifest** (fork R-D, written from capture onward by
B-cap), compute the orphan set `(owned ∩ present) − referenced`. The mirror of
`ViewModeModel::reconcile(liveGuids)`, one level down (files instead of GUIDs).
CONTEXT.md §Prune (Module architecture — pure).
**Verify:** CTest green. **Prune null test:** a folder whose every file is
referenced deletes nothing; prune returns exactly `(owned ∩ present) − referenced`
and nothing else. Referenced-set unioned across every bank (a file referenced by any
bank — including via a copy — is never an orphan); a present-but-not-owned file (a
hand-dropped file) is never an orphan.

- [x] Prune-reconcile pure function: `(present, referenced, owned) → orphans`,
  computing `(owned ∩ present) − referenced`; referenced unioned across the whole
  book (copies keep a file alive).
- [x] Tests: prune null test (all-referenced → empty); orphan = (owned∩present)−
  referenced; a copied file referenced by a second bank survives; a present-but-
  unowned (hand-dropped) file is never reclaimed; empty folder / empty book / empty
  manifest edge cases.

**Notes/decisions:**
- New pure module `src/prune_reconcile.{h,cpp}`: exports `pruneOrphans(present,
  referenced, owned)` (the safety-critical set algebra), `buildPruneReport`
  (count/bytes/display-capped list, unit-testable), and `pruneDeletePlan` (the R3
  confirm-time staleness intersection — `confirmed ∩ freshOrphans` in confirm order).
  Exact-string path match throughout (no case-folding, no separator normalization).
  `BankBook::referencedPaths()` additive const union query (all banks incl. pool,
  de-duped) added to `bank_book`. New `prune_reconcile_tests` CTest target.

---

## R2 — prune shell + persist wiring (filesystem I/O, thin)
**Goal:** Enumerate the current project bank folder (M4 project-relative resolution),
supply the referenced-set and the **owned-file manifest** (from B-cap) from the
session, feed the pure core, and produce a dry-run manifest. No deletion in this
wave — the report path only. CONTEXT.md §Prune (persist / prune shell).
**Verify (in DAW):** Dry-run reports the orphan count + reclaimed size (+ file list
for a small set) against the resolved current bank folder; resolves paths the same
way the index does (survives a Save-As relocation); deletes nothing.
**Depends on:** R1, B1, B2.

- [x] Prune shell: enumerate the resolved current bank folder; feed the pure core.
- [x] Session supplies the referenced-set (union across the book) **and the
  owned-file manifest** (written by B-cap); resolve the bank folder via the M4
  project-relative machinery.
- [x] Dry-run manifest: orphan count + reclaimed size (+ files for a small set);
  **no deletion in this wave.**

**Notes/decisions:**
- `ReaSamplerSession::pruneDryRun()` (read-only, non-throwing) enumerates the
  resolved current bank folder, unioning `book().referencedPaths()` and
  `owned().paths()`, feeds `pruneOrphans`, and calls `buildPruneReport` with a 64-file
  display cap. Pure `bankRelativeForName` (`capture_paths`) normalizes the folder-
  enumeration spelling to match the index convention so the pure core's exact-string
  match lines up. Forever-stable `BANK_PRUNE_FOLDER` action registered (dry-run report
  to console in R2; deletion wired in R3 behind the same action id).

---

## R3 — deletion + action (the destructive step, guarded)
**Goal:** The confirmed deletion step, the bindable "Prune bank folder" action, and
a `bank_panel` prune button: dry-run-first, confirm-with-manifest, then reclaim the
orphan set — via OS trash where portably available (fork R-C), else unlink.
CONTEXT.md §Prune (guardrails, API).
**Verify (in DAW):** "Prune bank folder" (action or panel button) reports first,
deletes only on explicit confirm, and reclaims exactly the orphan set — never a
referenced file, never a hand-dropped non-bank file; the referenced/owned-set safety
holds; deletions route to OS trash where available; non-bank and capture invariants
untouched.
**Depends on:** R2 (and B-cap's owned-file manifest). All forks settled 2026-07-24.

- [x] "Prune bank folder" action (`command_id`/`gaccel`/`hookcommand`),
  dry-run-first, confirm-to-delete.
- [x] `bank_panel` prune button (fork R-E) that fires the "Prune bank folder"
  action through the existing command-id contract — the panel affordance alongside
  the bindable action; split: button hit-test/layout is pure (mirror of
  `mode_switch`/`bank_grid`), draw + dispatch is bank_panel shell.
- [x] Deletion mechanism (fork R-C, settled trash-preferred): route to OS trash
  where a portable move-to-trash is verified available, else unlink behind the
  dry-run/confirm guardrail.
- [x] Orphan attribution (fork R-D, settled owned-file manifest): reclaim only
  `(owned ∩ present) − referenced` — the bank system's own leavings, never a
  hand-dropped folder file. (Manifest written by B-cap; consumed via R1/R2.)

**Notes/decisions:**
- Deletion is guarded: dry-run → REAPER `ShowMessageBox` confirm (count+bytes+files)
  → `pruneDeletePlan` staleness intersection (confirmed ∩ fresh pure-core output) →
  delete exactly the plan. Zero ext-state writes, no undo point (file deletion is not
  REAPER-undoable by design).
- **Windows:** routes to Recycle Bin via `SHFileOperationW` + `FOF_ALLOWUNDO`
  (verified against SDK 10.0.26100). **macOS / Linux:** no portable SWELL trash
  surface; falls back to `unlink` behind the dry-run/confirm guardrail.
- Manifest entries are deliberately NOT removed on deletion (the owned-file manifest
  algebra self-cleans: a deleted file will drop from `present` on the next prune scan,
  and `pruneOrphans` returns `(owned ∩ present) − referenced` — the absent file
  contributes nothing regardless).
- New pure module `src/prune_button.{h,cpp}`: layout (`computePruneButton`) and
  hit-test (`hitTestPruneButton`) for the footer prune button, right-anchored,
  suppressed gracefully when the footer is too narrow. Mirror of `mode_switch` /
  `tab_strip`. New `prune_button_tests` CTest target.
- `bank_panel` footer button dispatches `BANK_PRUNE_FOLDER` via `Main_OnCommand`
  through the registered command id (the same action as the bindable menu entry —
  no duplicate logic).

---

## Milestone 11 — polish (wave 1)
**Goal:** Batch capture (per selected item / per razor area), action trigger buttons
+ keybinding help labels, conform-on-insert. CONTEXT.md Build order 11.
**Verify (gates 23/23 both configs):** CTest green on new pure targets; each
in-panel action fires through the command-id contract without regressing precision
invariants.

- [x] **Batch capture** (`batch_capture` pure module + `CAPTURE_BATCH_ITEMS` /
  `CAPTURE_BATCH_RAZOR` actions): plan source ranges → ordinal units; mixed-result
  aggregation; actions fire one bank sample per selected item / per razor area;
  transient per-unit selection with RAII restore; per-unit invariants + provenance;
  single persist per batch; one summary line. `RunCapture` internals extracted to a
  shared `captureAndIndexOne` helper (behavior identical). New CTest target
  `batch_capture_tests`.
- [x] **Action trigger buttons + keybinding help labels** (`action_buttons` pure
  module + bank_panel strip): strip layout/hit-test with min-width overflow-hiding
  and label formatting with "(unbound)" fallback; struct `ActionButtonRect`; a 28px
  LICE button strip in bank_panel between the split body and tail footer fires
  capture item/track, realtime start/cancel, insert native/conform, re-capture-from-
  source via `NamedCommandLookup` + `Main_OnCommand`; labels show live bindings via
  `kbd_getTextFromCmd`. Coexists with Phase R's prune button (footer). New CTest
  target `action_buttons_tests`.
- [x] **Conform-on-insert** — verified already shipped (both insert variants were
  registered actions since the insert milestone); no new code. Closes as
  verified-extant.
- ~~[ ] **Resample-and-mute-source** — Cut (fixed by Daniel, 2026-07-26).~~ Rationale:
  the Design View mode projection (park/hide inactive-mode content) supersedes the
  mute-after-capture workflow; a mute action would be redundant with the dual-canvas
  architecture. Mirror of the null-test cut precedent ("Cut (fixed by Daniel)").

## Milestone 11 — polish (wave 2 / completion)
**Goal:** Native OS drag-out — the final M11 polish item. CONTEXT.md Build order 11,
§Non-goals (drag-out deferred to last).
**Verify (gates 24/24 both configs):** Drag-out places a valid file in the OS target
without regressing the precision invariants; copy-only semantics throughout (no source
deletion on drop); internal move/copy drag unchanged.

- [x] **`drag_out` pure module** (gesture-boundary decision): internal drag becomes
  OS-bound when the pointer leaves the panel client rect; path-list assembly with
  dedupe and missing-file skip. No REAPER types at the boundary. New CTest target
  `drag_out_tests`.
- [x] **`drag_out_win` shell** (Windows): OLE `DoDragDrop` / `CF_HDROP`. Copy-only
  structurally — `DROPEFFECT_MOVE` is not offered and no source-deletion path exists;
  prune remains the sole file-deleter. macOS/Linux via `SWELL_InitiateDragDropOfFileList`
  with a documented copy-semantics caveat (SWELL does not expose a drop-effect query).
- [x] `bank_panel` additive hook only — internal move/copy drag unchanged.

**Notes/decisions:**
- Copy-only is structural, not a policy flag: `DROPEFFECT_MOVE` is never offered on
  Windows, so the OS never signals a move. The SWELL path cannot query drop-effect;
  copy semantics are documented as a known caveat for macOS/Linux.
- Prune remains the sole authority for deleting files off disk; drag-out does not
  remove the source file or any bank index entry.
- This wave completes **Milestone 11** in full.

## Phase R forks — settled 2026-07-24
- **Fork R-C — deletion mechanism.** Settled: **trash-preferred, unlink fallback.**
  Route to OS trash where a portable move-to-trash is available (recoverable), else
  unlink behind strong dry-run/confirm. Per-platform trash surface verified at build:
  Windows `SHFileOperationW` + `FOF_ALLOWUNDO` (SDK 10.0.26100); macOS/Linux no
  portable SWELL trash surface → unlink fallback. Folded into R3.
- **Fork R-D — orphan attribution.** Settled: **owned-file manifest**,
  `(owned ∩ present) − referenced`; folder-sweep rejected as unsafe. **Seam lands
  early** — the manifest is written from capture onward (new **B-cap** point in
  Phase B), not reconstructed at prune time; R1/R2 consume it. Persistence shape
  (sibling `"reasampler"` key vs. `banks` blob) resolved at build time: sibling
  `"owned_files"` key.
- **Fork R-E — trigger.** Settled: **manual action + `bank_panel` button**,
  dry-run-first, confirm-to-delete. No background sweep. The earlier optional
  delete-time "…and prune now" convenience was **not** selected — out of scope.
  Folded into R3.

Both docs of record: `docs/product/removal-and-prune.md` §Fork R-C/R-D/R-E and
CONTEXT.md §Prune (Settled forks).

---

# Phase L — Look-and-feel (system-wide visual design language)

> Separate phase namespace. Namespaced **`L` (Look-and-feel)**, orthogonal to and ungated
> by the M/D/B/R/V/S pillars. Authoritative spec: **CONTEXT.md §Phase L**. Product
> framing + settled decisions (DS-1/DS-2/DS-3): `docs/product/visual-design-language.md`.

## L1 — shared LICE drawing kit (the foundation)
**Goal:** Stand up the shared LICE-based drawing kit that every Phase L surface (L2 dock
panel, L3 VST editor) consumes — palette/theme module, pure component geometry/hit-test
helpers, LICE draw shell, and retirement of the GDI `DrawText` path in `bank_panel`.
CONTEXT.md §Phase L (Kit architecture). DS-1 (LICE + WDL, no external frameworks) and
DS-2 (Direction B Neon Console + Direction C spectral) are the governing settled decisions.
**Verify:** CTest green (`theme_tests`, `component_geometry_tests`). Each text-on-surface
pair in the palette clears its WCAG floor (tested). `bank_panel` text routes through
cached-font `text()` — GDI `DrawText` path retired. Double-buffer discipline preserved.

- [x] **`theme`/palette module** (`src/theme.{h,cpp}`): role→color mapping via one
  constants block (DS-2 revised — REAPER-grey neutral ladder + three-accent pastel
  system: `bg/base #2b2b2b` / `bg/panel #333333` / `bg/cell #3a3a3a` / `line/hairline
  #4a4a4a` / `text/primary #dcdcdc` / `text/dim #a8a8a8`; `accent/primary` pastel lime
  `#B0E098` = live/active/selected, `accent/secondary` pastel teal `#84D6D0` +
  `accent/tertiary` pastel purple `#C2AAE8` = categorical distinctions); `Role` enum
  carries the three accent roles; `roleColor`/`roleColorState` updated (Active/Dragging/
  Focus → primary accent); `spectralColor` is a pastel three-stop sweep anchored on the
  three accents (lime → teal → purple); WCAG contrast-floor helpers + tests (text/dim-on-grey
  AA body; three pastels on bg/cell + bg/panel at the 3:1 floor); interaction-state color
  model. Pure; no LICE types. New CTest target `theme_tests`.
- [x] **`component_geometry` module** (`src/component_geometry.{h,cpp}`): button/slider/
  list-row geometry + hover hit-test. Pure; no LICE or REAPER types. New CTest target
  `component_geometry_tests`.
- [x] **`draw_kit` shell** (`src/draw_kit.{h,cpp}`): LICE draw layer — `fillSurface`
  (micro-gradient + inner highlight/shadow), `drawButton`/`drawSlider`/`drawListRow`/
  `drawWaveform`, cached-font `text()` over four `LICE_CachedFont`s (kit-owned lifecycle),
  full interaction-state model, double-buffer preserved.
- [x] **GDI `DrawText` retirement in `bank_panel`**: all panel text now routes through the
  kit's cached-font `text()`; raw GDI `DrawText` path retired (the single biggest
  "temple os → modern" lever).

---

## L2 — dock-panel layout redesign
**Goal:** Full layout redesign of the `bank_panel` dock window — task-grouped action bar,
full M11-aware button inventory placed by cluster, entire panel drawn through the L1 kit.
CONTEXT.md §Phase L (L2 scope). DS-3 (thorough layout redesign, not a light re-skin) is the
governing settled decision; sequenced after M11 merged.
**Verify:** CTest green (`action_bar_tests`). The panel renders in the settled B+spectral
language through the L1 kit — chrome, buttons, tabs, grid cells, dividers all by palette
role with hover on interactive elements; remaining GDI text retired; single
`KitColor→LICE_pixel` boundary via the kit's `toLice` (exposed in `draw_kit.h`). Prune
button remains footer-set-apart + `warn`-colored; grid stays the centerpiece.

- [x] **`action_bar` pure module** (`src/action_bar.{h,cpp}`, `tests/test_action_bar.cpp`,
  CTest target `action_bar_tests`): task-grouped action-bar layout — clusters (Capture /
  Placement / Maintenance), per-button label + keybinding micro sub-rects, whole-trailing-
  button overflow, point→index hit-test. Pure; no LICE or REAPER types. Mirror of
  `mode_switch`/`bank_grid`/`action_buttons`.
- [x] **`bank_panel` redesigned**: full M11-aware button inventory placed and grouped by
  task cluster (Capture: capture item/track, batch items, batch razor, realtime; Placement:
  insert + insert-conform; Maintenance: re-capture, cancel-realtime); prune remains footer-
  set-apart + `warn`-colored; grid stays the centerpiece. Entire panel draws through the L1
  kit (chrome, buttons, tabs, grid cells, dividers) by palette role with hover on
  interactive elements; remaining GDI text retired; single `KitColor→LICE_pixel` boundary
  via the kit's `toLice` (now exposed in `draw_kit.h`).

---

## L4 — dock-panel button layout enhancement
**Goal:** Re-home the `bank_panel`'s L2 button inventory around *frequency and intent* —
three-zone structure: top toolbar (capture + placement + maintenance), bottom toolbar (Design
View tagging + switching), footer (narrow mode toggle · Tail button · Prune). A layout
re-home of buttons that fire existing actions; no new actions, no capture/placement behavior
change, no touching the "capture ≠ placement" principle. Independent of L3.
CONTEXT.md §Phase L (L4 dock-panel button layout). Product framing:
`docs/product/visual-design-language.md` §L4.
**Verify (in DAW):** the top toolbar fires every capture + placement + maintenance action; the
bottom toolbar tags/untags selected tracks and switches/toggles Arrange/Design/show-both; the
footer shows a narrow `[Arrange|Design]` toggle at the left, a Tail button that cycles tail
on click with button states, and the Prune button set apart at the right in `warn`; every
surface draws through the L1 kit in the DS-2 grey+pastel palette; capture and placement still
never auto-insert (the buttons only fire the existing, unchanged actions).

- [x] **Top toolbar**: capture cluster (capture item, capture track, batch items, batch razor,
  capture RT) + placement cluster (insert, insert-conform) + maintenance cluster (re-capture,
  cancel-realtime) moved from the L2 bottom bar to a top toolbar via `action_bar` row layout;
  buttons fire existing actions unchanged — no auto-insert.
- [x] **Bottom toolbar**: Design View action family as buttons (tag / untag selected for mode,
  activate Arrange, activate Design, toggle active mode, show-both) via `action_bar`
  `ActionCluster::Tagging` + `ActionCluster::Switching`; fires existing registered Design View
  actions.
- [x] **Footer toggle**: `[Arrange|Design]` segmented toggle shrunk to fit-its-text width and
  moved to the footer left of Prune; per-mode count as a compact adjacent label.
- [x] **Footer Tail button**: Tail click-zone converted to a proper kit button (rest/hover/
  pressed states; click still cycles the tail setting).
- [x] **Footer order** (`[Arrange|Design]` · Tail · … · Prune `warn` set apart at the right);
  pure footer-strip layout in new `footer_bar` module covered by CTest (`footer_bar_tests`).

**Notes/decisions:**
- **Maintenance cluster restored to top toolbar** (Daniel's directive during L4 build): the
  initial L4 spec described the top toolbar as "capture + placement" only; the landed
  implementation includes re-capture and cancel-realtime in a Maintenance cluster on the same
  top toolbar. CONTEXT.md and CLAUDE.md updated to reflect the actual layout.
- New pure module `src/footer_bar.{h,cpp}`: footer layout/hit-test (narrow mode toggle +
  Tail button + Prune); no LICE or REAPER types. New CTest target `footer_bar_tests`.
- `action_bar` gained `ActionCluster::Tagging` and `ActionCluster::Switching` for the
  bottom-toolbar Design View verb groups.

---

## L5 — dock-panel button refinements
**Goal:** Refine the L4 three-zone toolbar so the button faces read cleanly and group
legibly — an overflow menu for the rare capture variants, short faces with full-name
tooltips (no `ReaSampler:` prefix), an opposite-mode tag-button set, removal of the now-
redundant Toggle and Activate-Arrange/Design buttons, and semantic-grouping spacing.
**No new capture/placement behavior**; every button fires an existing registered action
(the "capture ≠ placement" principle is untouched). Ungated by Phase S; sequences after L4.
**Verify (in DAW):** the top bar shows only frequent capture/placement/maintenance buttons +
a right-anchored More (⋯) menu that fires Batch Items / Batch Razor / Capture RT; hover
tooltip shows the full action name with `ReaSampler:` prefix stripped; the bottom bar shows
four Item/Track × Arrange/Design tag buttons with only the opposite-mode pair live (disabled
pair visibly greyed via the kit `Disabled` state) and no Toggle button; cluster groups read
as groups. All buttons fire the same actions their keybindings do.

- [x] Top-toolbar overflow: Batch Items / Batch Razor / Capture RT pulled off the visible bar
  into a right-anchored **More (⋯) menu button** (kit-drawn button + `TrackPopupMenu` popup);
  each entry fires its existing command id. Pure layout owns the menu-button rect + hit-test
  (`overflow_menu` pure module); the popup + dispatch is shell.
- [x] Short faces + drop `ReaSampler:` prefix on the button *face*; keep the keybinding micro
  sub-row.
- [x] **Hover tooltip carrying the full action name (prefix stripped)** via a **custom LICE-kit
  hover-delay tooltip** (`tooltip` pure module): sourced from the registered action phrase
  (not `kbd_getTextFromCmd`); `ReaSampler:` prefix stripped at draw time; tooltip box width
  clamped to the client so it never overhangs a narrow dock. The keybinding sub-row still uses
  the live binding from `kbd_getTextFromCmd`.
- [x] Bottom-toolbar four tag buttons: **Item: Arrange / Item: Design / Track: Arrange /
  Track: Design**, wired to the existing item-move (`VIEW_MOVE_ITEMS_ARRANGE` /
  `VIEW_MOVE_ITEMS_DESIGN`) + track-tag (`VIEW_TAG_ARRANGE` / `VIEW_TAG_DESIGN`) actions.
- [x] **Opposite-mode enablement:** a button is live iff its target mode ≠ the active mode;
  otherwise drawn `Disabled` (kit disabled state, `TextDim`) and its click is a no-op. Pure
  predicate (`mode_enable` pure module) unit-tested; shell reads `view().activeModeId()` once
  per draw and applies.
- [x] **Activate-Arrange / Activate-Design / Toggle buttons removed** from the bottom toolbar
  (all three actions stay registered; footer toggle owns mode switching). **Show Both** kept
  as a set-apart button on the bottom toolbar.
- [x] Semantic-grouping spacing widened: `clusterGap` 16→24 (`buttonGap` remains 4; 6:1 ratio)
  on both toolbars so clusters read as groups.

**Notes/decisions:**
- **Activate-Arrange / Activate-Design / Toggle FORK resolved (Daniel):** all three removed
  from the bottom toolbar. The footer `[Arrange|Design]` toggle is the single mode-switch
  affordance; the bottom bar is tagging + Show Both only.
- **Tooltip mechanism resolved as custom LICE-kit hover-delay tooltip** (DS-1 "keep drawing in
  the kit"): avoids attaching a SWELL tooltip control to non-child LICE rects. SWELL is the
  Win32-emulation layer for macOS/Linux and is not the mechanism used here; on Windows the
  path is native, and the chosen implementation is a custom kit-drawn tooltip.
- New pure modules: `src/overflow_menu.{h,cpp}` (menu-button geometry/reserve/hit-test),
  `src/mode_enable.{h,cpp}` (opposite-mode enablement predicate), `src/tooltip.{h,cpp}`
  (placement + prefix-strip). New CTest targets `overflow_menu_tests`, `mode_enable_tests`,
  `tooltip_tests`.

---

## L6 — toolbar polish (in-DAW feedback refinement on L5)
**Goal:** Polish pass on the L5 dock-panel state based on Daniel's in-DAW feedback —
single-row button faces, keybinding surfaced in the hover tooltip, Cancel RT moved into
the overflow menu, and visible top-bar cluster order tidied. No new modules, no new test
targets, no capture/placement behavior change.

- [x] **Single-row button faces:** keybinding micro sub-row removed from `ActionBarSlot`
  (and `bindingHeight`/`minSplitHeight` removed from `ActionBarSpec`); buttons now show
  only the short label. Toolbar height 40→28 px.
- [x] **Keybinding in hover tooltip:** tooltip now renders "`phrase — binding`" when the
  action is bound, bare phrase when unbound (live binding via `kbd_getTextFromCmd`).
- [x] **Cancel RT moved into overflow menu:** the More (⋯) popup now lists four entries —
  Batch Items / Batch Razor / Capture RT / Cancel RT. The visible top bar no longer has a
  Cancel RT button.
- [x] **Visible top-bar cluster order:** Capture Item · Capture Track · Re-capture · Insert ·
  Insert Conform (cluster order: Capture → Maintenance → Placement).

**Notes/decisions:**
- Icons were considered and deferred (not implemented in this pass).

---

## L7 — capture ordering, card metadata, and selection styling
**Goal:** Three grid-facing improvements to the dock panel, drawn through the L1 kit in the
settled DS-2 palette. (1) **Persisted deterministic capture order + drag-drop reorder + sparse
placement:** each bank (and the pool) carries an explicit, persisted per-sample order via a
per-`Bank` id→slot `SlotMap` in `bank_book`; a card may sit in a slot that leaves earlier slots
empty (gaps preserved; trailing empty tail trimmed for scroll extent). (2) **Decorative metadata
over the peaks:** each card overlays capture length as **bars.beats.subdivisions (bottom-left)**
and **seconds.ms (bottom-right)** in the kit's micro / value-mono type class, `text/dim`. (3)
**Selection restyle:** a selected card drops the inverted accent-fill and instead draws the
*normal* cell + an **`accent/tertiary` (pastel purple `#C2AAE8`) border**. No new capture /
placement behavior; the "capture ≠ placement" principle is untouched.

- [x] **`SlotMap` in `bank_book`:** gap-preserving per-`Bank` id→slot map — persisted
  deterministic display order; interior gaps preserved / trailing tail trimmed; JSON rides
  inside the existing `"banks"` blob; pre-L7 migration seeds dense insertion order via
  `reconcileSlots()` on the load path. `bank_model` / `Sample` untouched by position (position
  is a per-bank display concern).
- [x] **`BankBook` mutators:** `reorderSample` (insert-before-shift; same-slot = no-op),
  `replaceSample` (occupant index-removal via the standard remove path + pool-guard inheritance;
  no-op on reject), `orderedSampleIds`, `reconcileSlots`. All gap-preserving; deterministic;
  CTest-covered.
- [x] **`Sample` meter stamp (ONE sanctioned `Sample` change):** `captureTimeSigNum` /
  `captureTimeSigDenom` added to `Sample` + JSON round-trip; stamped on both capture paths and
  refreshed on re-capture via `TimeMap_GetTimeSigAtTime` (API confirmed at build). Old samples
  with no stamp fall back gracefully (blank musical read-out).
- [x] **`card_drag` pure module:** gesture precedence — leave-client → OS drag-out;
  other-bank → move/copy; same-bank → reorder / Alt-over-occupied → replace. Cursor-cue map
  returned as the pure resolved gesture. Sparse `computeSlotRects` / `hitTestSlot`. SWELL stock
  cursors chosen at build: Reorder→`IDC_SIZEALL`, Move→`IDC_HAND`, Copy→`IDC_UPARROW`,
  Replace→`IDC_SIZEWE`. New CTest target `card_drag_tests`.
- [x] **`card_meta` pure module:** bars.beats.subdivisions from the stamped tempo + meter;
  seconds.milliseconds rounded. Both blank when the sample is unstamped. New CTest target
  `card_meta_tests`.
- [x] **`bank_panel` sparse-grid render:** grid renders in sparse slot order; decorative
  empty-gap cells drawn for unoccupied slots; every cell↔sample consumer remapped to
  id-based occupied-ordinal space (selection, keyboard nav — arrows skip gaps, audition,
  multi-select, delete / re-capture resolution, drags).
- [x] **`bank_panel` drop dispatch:** reorder / Alt-replace / move-copy drop with one-Ctrl-Z
  undo via the existing batched undo pattern; per-slot drop highlight (`accent/hot`, doubled
  outline for replace); SWELL stock cursor cues via `SetCursor` per the pure resolved gesture.
- [x] **`bank_panel` metadata overlay:** bars.beats bottom-left (Micro), s.ms bottom-right
  (ValueMono), `TextDim`, decorative / non-interactive.
- [x] **Selection restyle:** normal cell + `accent/tertiary` purple border; inversion removed;
  focus ring distinct from the selection border.

**Notes/decisions:**
- **M9 overlap (awareness note — unchanged intent).** M9 (capture-to-slot-N / insert-slot-N,
  MIDI-bindable, MPC-style) remains **explicitly deferred (Daniel, 2026-07-26).** The
  interchangeable-slot substrate L7 builds still eases a future M9 revival but L7 adds **no**
  slot-numbered capture/insert actions and **no** MIDI bindings. The "plain vs. M9-shaped"
  sub-fork is closed: plain gap-preserving substrate (F2).
- **Build-time choices confirmed:** `TimeMap_GetTimeSigAtTime` confirmed at build for the
  meter stamp; SWELL stock cursors chosen (no custom cursor load/synthesis required);
  gap navigation = skip gaps (arrow keys skip empty slots); same-slot reorder = no-op.
- New CTest targets `card_drag_tests`, `card_meta_tests`.

---

## L3 — VST editor + embed-strip restyle
**Goal:** Bring the ReaSampler 9000 VST editor (`IPlugView` LICE surface,
`reasampler_editor.cpp`) and the S6 embed strip (`reasampler_embed.cpp`) up to the
settled-and-revised **B + three-accent pastel** look via the L1 kit: kit cached-font
`text()` (the kit's current face — no font change), kit component draws, the
**REAPER-grey neutrals** (`bg/base #2b2b2b` / `bg/panel #333333` / `bg/cell #3a3a3a`)
with the **three pastel accents** (primary lime / secondary teal / tertiary purple), the
**pastel spectral keyboard strip + zone bars** (active zone lifts to `accent/primary` +
a static glow) as the signature surface, and hover/pressed/drag interaction states
throughout. Merged as `c53683e`. **L3 was the last remaining Phase L point — Phase L
is now complete (L1, L2, L3, L4, L5, L6, L7 all landed).**
**Verify (in DAW):** the VST editor + embed strip render in the settled B + three-accent
pastel language through the L1 kit — kit AA cached-font text, gradient/rounded kit
components, the pastel spectral keyboard strip, working hover/pressed/drag; the VST3
class UID is unchanged (a visual refresh is not a compat event).

- [x] Route the VST editor's + embed strip's text through the kit's cached-font
  `text()`; retire their raw GDI `DrawTextA` path (retired in both shells).
- [x] Retire the shells' **local pre-L1 palette** — the `kColBackground`/`kColCardBg`/
  `kColThumb`/… forest-green-on-charcoal constants block in `reasampler_editor.cpp`
  (and the mirrored constants in `reasampler_embed.cpp`) — and draw every surface
  through the L1 `theme` roles. One kit, one look; two palettes collapsed to one.
- [x] Restyle the editor + embed components through the kit (capture-first browser
  search/tabs/thumbnails, channel toggles, ADSR + pitch sliders, Varispeed/Preserve mode
  toggles, zone bars, list rows, waveform + start/loop markers, segmented controls) in
  the B (Neon Console) palette with hover/pressed/drag states throughout.
- [x] Apply **Direction C's pastel spectral treatment** to the keyboard strip + zone bars:
  hue-mapped zones as a pastel sweep anchored on the three accents; active zone lifts to
  `accent/primary` + a static glow (no animation); waveform + loop/start markers drawn
  through `drawWaveform` + `warn`/accent marker roles; VST3 class UID unchanged.

**Notes/decisions:**
- **Full restyle, not a born-in-kit no-op.** The Phase S surfaces (`reasampler_editor.cpp`
  + `reasampler_embed.cpp`) arrived on dev drawing flat `LICE_FillRect` blocks + raw GDI
  `DrawTextA`, off a local pre-L1 forest-green palette (`kColBackground` etc.) — the
  coordination contract's "born in the kit" branch did not occur. L3 performed the full
  restyle and reconciled the two palettes into one.
- **Shell-side only.** All `src/vst/` UI geometry modules (`editor_geometry`,
  `keyboard_strip`, `waveform_view`, `capture_browser`, `param_slider`, `browser_scroll`,
  `embed_strip`) are pure geometry/hit-test — zero LICE, zero draw. L3 touched only the
  two draw shells; no geometry rework was needed.
- **Beta title band — textual-only distinction (Daniel, 2026-07-27).** The S18 beta
  channel title band gets no distinct visual accent; L3 restyles it in the standard B
  pastel palette and the beta-vs-stable distinction stays purely textual (the
  channel-derived plugin name via `app_version`, as before). No channel-specific accent
  color. Closes the one open fork from the L3 readiness review.
- **VST3 class UID unchanged.** A visual refresh is not a compat event; RT/`process`
  path untouched; pure geometry modules remained pure throughout.

---

# Phase S — MIDI-playback instrument (native VST3 sampler; a second build artifact)

> **Landed on dev (merged 2026-07-27); DAW verification pending Daniel's smoke test.**
> S1–S18 are all on dev. The cross-artifact ingest relay (one S13 bullet) was explicitly
> DEGRADED and remains deferred in `PLAN.md`. Authoritative spec: **CONTEXT.md
> §MIDI-playback instrument — additive phase spec (Phase S)**. Product framing:
> `docs/product/midi-playback.md`.

---

## S3 — pure sampler core (voice engine / envelope / keymap / repitch)
**Goal:** The REAPER-free **and** VST3-free sampler core — voice allocation/polyphony,
amplitude envelope (ADSR), key→sample and velocity→sample mapping (the keymap),
repitch/interpolation from root note, keymap resolution — unit-tested in CTest against
known signals. **The heart of the phase (D3); the mirror of
`bank_model`/`peaks`/`view_mode_model`/`bank_book`; test it hard.** The core is
invariant under the build-shape choice — no VST3 or REAPER type at its boundary.
CONTEXT.md §Phase S (pure core, module architecture).
**Verify:** CTest green. Voice allocation is correct under polyphony (note-on/off,
voice stealing where bounded); ADSR shape asserted against a known signal (mirror of
`peaks`); repitch from root note produces the expected pitch ratio; keymap resolution
maps a (note, velocity) to the correct sample/zone; the core takes and returns only
plain data (no VST3/REAPER types) — enforced by the test target linking neither SDK.
**Depends on:** S2 (consumes `rootNote` / loop points as core inputs).

- [x] Voice engine: polyphonic voice allocation (note-on/off, bounded voice stealing),
  per-voice state, mono-and-basic-polyphony sufficient for Tier 0.
- [x] Amplitude envelope (ADSR) math — asserted against a known signal.
- [x] Repitch/interpolation from root note (chromatic pitch ratio across the
  keyboard); loop-point-aware sustain for held notes.
- [x] Keymap model + resolution: key ranges/zones (Tier-1 shape) and the
  (note, velocity) → sample/zone query; Tier-0 chromatic-from-single-root as the
  degenerate case.
- [x] Tests: voice allocation under polyphony + stealing; ADSR envelope shape;
  repitch pitch-ratio correctness; keymap resolution (single-root chromatic + zoned);
  core boundary is plain-data-only (no VST3/REAPER types).

---

## S4 — Tier 0: "the bank plays" (single sample, chromatic)
**Goal:** The honest MVP — one bank sample mapped chromatically across the keyboard
from its root note, basic polyphony, a simple amp envelope, velocity→volume. Wire the
S3 core into the S1 VST3 shell over the live-state seam (bridge-read bank + audio via
the M4 project-relative path machinery). Editor deferrable behind a parameters-only
default view. CONTEXT.md §Phase S (Tier 0, seams). **Delivers the core promise.**
**Verify (in DAW):** on an instrument track, the VST3 plays a chosen bank sample
MIDI-triggered, repitched chromatically from its root note, with basic polyphony,
an amp envelope, and velocity→volume; it reads the live `"reasampler"` bank via the
bridge and resolves the WAV audio the same project-relative way `persist` does;
following the active project works; it never captures and never inserts into the
arrange (read-only over the bank).
**Depends on:** S1, S2, S3.

- [x] VST3 `process` marshalling: read MIDI note-on/off/velocity off the event bus,
  drive the S3 core, write per-voice audio to the output bus. (Block-granular event
  timing at Tier 0; sample-accurate offset scheduling is a later tier.)
- [x] Live-state seam: read the bank index + selected sample's root note from
  `"reasampler"` ext-state via the bridge; resolve the WAV audio path the M4
  project-relative way (shared convention with `persist`, not re-implemented — the
  parent-of-.rpp derivation is extracted to `capture_paths::projectDirOfRpp`, which both
  `persist` and the bridge call). Bank JSON parsed via the shared `bank_book` path (the
  spike string-scan reader retired); ext-state key names shared via pure `ext_keys.h`.
- [x] Sample selection UI (minimal, in the `IPlugView` LICE editor): a clickable list
  of the bank's samples; the pick is the instance's own VST3 component state
  (setState/getState), never written back to the bank.
- [x] Tier-0 playback: chromatic-from-root, basic polyphony (16 voices), amp envelope,
  velocity→volume — plays in REAPER's routing/record/render path like any VSTi. Sample
  load / decode / keymap build happen off the audio thread and hand to `process` via a
  lock-free atomic pointer swap (graveyard-reclaim); `process` never allocates.

---

## S5 — Tier 1: "a keymap" (zoned multisamples, per-sample root notes)
**Goal:** Multiple bank samples zoned across the keyboard (key ranges), each with its
own root note — a captured *kit* (one-shots) or a *multisampled instrument* (same
instrument sampled at several pitches) plays correctly. One sample per key-region.
CONTEXT.md §Phase S (Tier 1). **Where the root-note + key-range seam fields earn
their place.**
**Verify (in DAW):** a keymap of several bank samples plays correctly zoned across
the keyboard, each repitched from its own root note within its range; a captured kit
and a multisampled instrument both play as expected; the keymap is authored in the
instrument (performance map) while root notes come from the bank intrinsics (S2);
editing the keymap does not touch the bank.
**Depends on:** S4.

- [x] Keymap editor in the `IPlugView` LICE editor: assign bank samples to key ranges
  (low/high note per sample), each with its own root note (from S2 intrinsics,
  overridable in the performance map).
- [x] Tier-1 playback: zoned resolution — a note picks its zone's sample and repitches
  from that sample's root note; one sample per key-region.
- [x] Performance-map persistence: the keymap (zones, per-sample assignment) is the
  instrument's own state — held in the instrument as VST3 component state (setState/getState)
  per D-B's data-ownership split; the live `"reasampler"` seam is read-only (bank +
  intrinsics in, nothing written back), never written back as a bank intrinsic.

---

## S6 — embedded TCP/MCP UI (D-D — scheduled in-phase, after the editor)
**Goal:** Render a compact keymap/level strip **inline in the track/mixer control
panel** via `reaper_plugin_fx_embed.h` (`IReaperUIEmbedInterface`) — the same
Cockos surface REAPER's own embedded FX use — so the instrument draws inline, not only
in its own window. Composes with the S1/S5 LICE editor path (same LICE-class drawing).
**Scheduled, not deferred (D-D settled 2026-07-26):** a real later point, sequenced
last because it is polish over a Tier-0 need — but on the roadmap. CONTEXT.md §Phase S
(embedded UI, D-D).
**Verify (in DAW):** the instrument draws a compact inline strip in the TCP/MCP (not
only its own editor window); the inline surface reflects and (where offered) edits the
keymap/levels; the embed lifecycle is clean (open/close/resize); the same LICE drawing
as the main editor is reused.
**Depends on:** S5 (composes over the existing LICE editor). **Must-verify before
build:** the `IReaperUIEmbedInterface` contract + embed message/lifecycle against
`vendor/reaper-sdk/sdk/reaper_plugin_fx_embed.h`.

- [x] Implement `IReaperUIEmbedInterface` on the VST3; draw a compact keymap/level
  strip inline in the TCP/MCP using the same LICE surface as the editor.
- [x] Embed lifecycle (open/close/resize/hit-test inline) handled cleanly; reflects
  the live keymap/levels.

---

## S7 — stereo channel mode (mono | stereo; core channel dimension + bus negotiation)
**Goal:** Give the instrument a per-instance **channel-mode toggle — 1 (mono) or 2
(stereo)** — that "works with the REAPER audio bus automatically." Mono keeps today's
downmix path; stereo grows the S3 core a **channel dimension** (2-channel sample data,
per-voice stereo render, stereo interp/loop) and negotiates the VST3 output bus so
mono/stereo just works in REAPER's routing. **This is an S3-core extension, not a shell
hack** — it touches the engine Daniel smoke-tests, so it sequences first after the
editor/embed work. CONTEXT.md §Phase S (channel mode, D-E). **Decided direction
(2026-07-26); leans below are build-time residuals, not open forks.**
**Verify (in DAW):** an instance set to stereo plays a stereo capture in true stereo,
its VST3 output bus negotiated to 2 channels via `setBusArrangements` so REAPER routes it
without manual channel wiring; an instance set to mono plays the existing downmix path; a
mono source in stereo mode plays dual-mono (centered); a stereo source in mono mode
downmixes (existing policy); the mode is per-instance state that survives project
save/reopen (component state, like the selected sample); the pure core's stereo render is
asserted against a known two-channel signal (mirror of `peaks`), and mono behavior is
unchanged (regression).
**Depends on:** S3 (extends the core), S4 (extends the process/bus shell). Independent of
S8/S9.

- [x] Core channel dimension (pure, S3 extension): `SampleData` carries 1- or 2-channel
  decoded PCM (`frames` + optional length-matched `framesR`; `channelCount()`);
  `Voice::renderFrameStereo` + a `VoiceEngine::render(left,right,n)` overload produce a
  per-channel frame sharing one read head + one envelope tick; stereo linear interpolation +
  loop read per channel. Mono stays the degenerate case (`renderFrame` reads channel 0 only,
  byte-identical). Tests: stereo render asserted against a known 2-channel signal; dual-mono;
  per-channel repitch + additive mix; mono render unchanged (regression) — sampler_core_tests.
- [x] Channel-mode toggle as per-instance state: `ChannelMode {Mono,Stereo}` in the
  instrument's own component state (v4 = v3 + a channel-mode byte; setState/getState);
  default mono. Cross-mode policy in `decodeChannels`: **mono source + stereo mode →
  dual-mono**; **stereo source + mono mode → downmix** (existing decode-side policy). The
  toggle lives in the instrument, never written to the bank (D-B). v1/v2/v3 blobs lift to v4
  with mono default; round-trip + lift tests — sample_map_tests.
- [x] Shell: `decodeRelative` fills 1- or 2-channel `DecodedZonePcm` per the active mode
  (source channel count from the WAV layout); the process path renders the host's negotiated
  output channel count (stereo into ch0/ch1, mono into ch0) — RT discipline unchanged.
- [x] VST3 bus negotiation: `setBusArrangements` accepts only the mode's arrangement
  (kMono/kStereo), else rejects (kResultFalse) but keeps a valid mode arrangement so
  `getBusArrangement` (base default) reports it; a runtime mode change repoints the output bus
  + calls `restartComponent(kIoChanged)` so REAPER re-negotiates. **Verified** against the
  vendored Steinberg SDK (`ivstaudioprocessor.h` contract, `vstsinglecomponenteffect.cpp`
  base impl, `ivsteditcontroller.h` kIoChanged); see handoff notes.

---

## S8 — ingest through the bank (one gesture: capture/import into bank + assign to instance)
**Goal:** Loading a sample into the sampler is **one gesture** — capture/import-into-bank
**and** auto-assign to the active sampler instance. **The extension owns ingest** (it has
arrange access, media-explorer access, and drop-target surface on its own panels); the
instrument stays a **read-only bank consumer**. This lives in the *extension* codebase
(actions + bank_panel + capture/insert), routing through the existing capture add-path and
the live `"reasampler"` seam the instrument already reads. CONTEXT.md §Phase S
(ingest-through-bank contract). **Decided direction "option 1" (2026-07-26).**
**Verify (in DAW):** a one-click "capture selected item / time-selection into the bank and
assign to the active instance" action captures via the existing capture path (never
auto-inserting into the arrange — load-bearing principle intact) and the target instance
plays the new sample on its next reload; a Media Explorer file imports into the bank and
assigns the same way; a file dropped onto a ReaSampler panel surface ingests into the bank
and assigns; the instrument never captures or imports (read-only over the bank throughout).
**Depends on:** S4 (an instance to assign to), M7 capture add-path, B2 (active-bank add
target). Best paired with S9 so assignment refreshes hands-free; functional without it
(assign triggers a reload on the target instance directly).

- [ ] "Capture selected item / time-selection into bank + assign to active instance"
  action (`command_id`/`gaccel`/`hookcommand`, MIDI-bindable): reuse the existing capture
  request path (`CountSelectedMediaItems`/`GetSelectedMediaItem` + `GetSet_LoopTimeRange`
  as the capture inputs), add the resulting `Sample` to the active bank, then assign its
  id to the target instance. **Never inserts a timeline item** (capture/placement stay
  separate — the assignment is a bank-index + instance-selection act, not a placement).
- [ ] Media Explorer import → bank → assign: read the Media Explorer's current selection
  via `MediaExplorerGetLastPlayedFileInfo` (path + selection range), import the file into
  the bank (existing import/capture add-path), assign to the target instance. **Honest SDK
  limit (verified against the vendored headers):** the Media-Explorer surface is thin —
  `OpenMediaExplorer` (open/select) + `MediaExplorerGetLastPlayedFileInfo` (read the *one*
  last-played/selected file + its range) are the whole contract; there is **no**
  enumerate-selected-files and **no** register-a-drop-handler-on-the-Media-Explorer API.
  So ME import is *single-file, pull-on-action* (an action the user fires while a file is
  selected in the ME), not a push/drop from inside the Media Explorer. **Spike:** confirm
  `MediaExplorerGetLastPlayedFileInfo` returns a usable path+range for a merely-*selected*
  (not-yet-played) file, or whether a play is required first.
- [ ] Drag-and-drop onto ReaSampler surfaces: accept an OS file drop onto the docked
  `bank_panel` (and its bank/tab regions) → ingest into the bank → assign. **Honest SDK
  limit (verified):** REAPER exposes **no** drag-drop registration API; drop handling is on
  ReaSampler's *own* HWNDs via SWELL/Win32 (`WM_DROPFILES` / an `IDropTarget` on the panel
  HWND), the same surface the panel already owns. **Assess-and-flag (spike, do not promise
  here):** a drop *onto the VST3 editor window* — whether the `IPlugView` HWND can accept an
  OS file drop and relay it to the extension as a bank-ingest request (the instrument does
  **not** ingest; it forwards a request to the extension over an agreed seam). Reported
  honestly as a spike because it crosses the two-artifact boundary and the relay mechanism
  is unproven; if it proves gnarly, drop-onto-panel is the shipped path and drop-onto-editor
  is deferred.
- [ ] "Assign to instance" seam: how the ingest action names the target instance and hands
  it the new sample id. Lean (build-time residual, not a fork): the active/last-focused
  instance is the target, discovered via the host context the bridge already resolves; the
  assignment is the same instance-owned selection state S4 already persists, so a reload
  picks it up. If the change-detection seam (S9) exists, assignment refreshes hands-free;
  without it, the ingest action pokes the target instance's reload directly.

---

## S9 — bank-generation change-detection (recapture / ingest refreshes instances hands-free)
**Goal:** Because instances reference sample **ids**, a **recapture** (M10) landing under
the same id — or an **ingest** (S8) touching the active bank — should refresh playing
instances **hands-free**, without the user re-opening each editor. Add a **bank-generation
counter** to `"reasampler"` ext-state that the extension bumps on any bank-content
mutation, and that the instrument polls off the audio thread on a safe cadence, calling its
existing `reloadFromBank()` when the generation changes. CONTEXT.md §Phase S
(bank-generation seam). **Closes the missing change-detection trigger the recapture
auto-update story needs.**
**Verify (in DAW):** a recapture that regenerates a sample already assigned to a live
instance refreshes that instance's playback within a bounded cadence, no editor re-open; an
ingest (S8) that updates the active bank likewise refreshes assigned instances; the poll
runs off the audio thread (never in `process`) and triggers the existing off-thread reload
path; instances not referencing a changed sample do not audibly glitch (reload is atomic —
the S4 graveyard-reclaim handoff); a project with no generation stamp (pre-S9) defaults
cleanly (treated as generation 0; first bump refreshes).
**Depends on:** S4 (the off-thread `reloadFromBank` + atomic handoff this drives). Writer
side is extension-only and independent of S8; consumed by S8 and M10 recapture. Best landed
alongside S8.

- [x] Writer (extension): a monotonic **bank-generation counter** stamped into
  `"reasampler"` ext-state (new `ext_keys.h` constant — forever-stable spelling), bumped
  on every bank-content mutation that changes what an instance would play (capture add,
  recapture-in-place, sample-remove, move/copy affecting the active bank). Additive to the
  persist blob; defaults to 0 for projects saved before the stamp exists.
- [x] Reader (instrument): poll the generation over the bridge on a safe **off-audio-thread
  cadence** (a UI/timer tick, not `process`), compare to the last-seen value, and call the
  existing `reloadFromBank()` on change — reusing S4's atomic pointer-swap handoff so a
  refresh mid-play does not glitch. No new audio-thread work; no allocation in `process`.
- [x] Cadence + coalescing: pick a poll interval that is responsive but cheap (build-time
  residual — a low-frequency UI timer, coalescing multiple bumps between polls into one
  reload). **Must-verify before build:** that a bridge ext-state read on the instrument's
  UI/timer thread is safe against a concurrent extension write (the read already tolerates a
  stale value by design — it reloads on the *next* poll; confirm no torn-read hazard for the
  single integer generation key).

---

## S10 — capture-first editor: browser + guided single-capture setup ("ReaSampler 9000" UX overhaul, part 1)
**Goal (REVISED 2026-07-26 — workflow-first reframe, Daniel):** Rebuild the editor's
default face around the **primary flow = one capture, fast**, not a keymap. A giant list of
"item" blocks is visually useless; most instances play a *single capture*, and zones are a
nice-to-have. So the default view is a **capture browser** (scannable cards with peak
thumbnails, name, root/key badge; **bank filter**) feeding a **guided single-capture setup**
(root note, play-mode basics, level) — and the keyboard strip serves the *single-capture*
case first (shows where the capture sits / its root). **Time-to-first-note is the metric.**
Multi-zone keymap editing is **demoted to an opt-in "Zones" panel** (S10-Z below), not the
default. The keyboard-strip drag machinery is still built here, but in service of the
capture-first layout. All layout/hit-test math is **pure geometry** (new `keyboard_strip` +
a `capture_browser` layout module — mirrors of `mode_switch`/`editor_geometry`); the LICE
draw + drag-state machine is the editor shell. RT discipline untouched (edits commit
off-thread via `commitMapAndReload`); the instrument stays a **read-only bank consumer**.
CONTEXT.md §Phase S (ReaSampler 9000 UX — capture-first editor).

**Policy reversal — fresh instance is SILENT, nothing auto-selected (was S4).** The S4
"first sample plays" fallback is **removed**: on open with no stored selection, the
instrument plays **nothing** and the editor shows a clear **empty state** ("pick a capture")
— it does not auto-play sample #1. Retires the `selectSample` first-sample fallback
(`sample_map.cpp` "No stored id → fall back to the FIRST sample") and the processor's
Tier-0 fallback that resolved it; an empty stored id now resolves to silence. A capture is
loaded when the user picks one (or via S13 drop-to-load / S8 ingest). This is a deliberate
reversal of the S4 convenience default, not a regression.

**Verify (in DAW):** a fresh instance plays **nothing** and shows the "pick a capture"
empty state (no auto-play of sample #1); the capture browser draws **peak thumbnails**
(the `Sample` peaks bank_model already carries — same data the dock panel thumbnails use),
name, and a root/key badge where present, and is **filterable by bank** (bank_book named
banks); picking a capture loads it, shows it (waveform/peaks + its root on the keyboard
strip), and it plays repitched from its root; time-to-first-note is a pick-then-play, not a
list-scroll; the keyboard strip shows the single capture's root and is draggable to set it;
the pure geometry modules are CTest-green (browser card/grid layout + hit-test; strip
edge-grab/body-move/key→note) with no host types at their boundary; the ±1 nudge-button row
is gone.
**Depends on:** S4 (the selection state + reload path this reverses the fallback on), S1
(the LICE `IPlugView` drag/event routing — extends the click-only `wndProc` to
`WM_MOUSEMOVE`/`WM_LBUTTONUP`), S5 (the `PerformanceMap`/zone model the opt-in Zones panel
edits — but the default face does not require a keymap). **Adopts the Phase L kit when
available — not gated on Phase L.** S10 builds its browser cards + keyboard strip with the
current LICE drawing; when Phase L's L1 kit lands on `dev`, this surface adopts it (the one
source of drawing). The drag machine's `WM_MOUSEMOVE` tracking also lights the kit's
**hover** states at near-zero marginal cost once the kit is present.

- [ ] No-auto-select + empty state (the policy reversal): remove the `selectSample`
  first-sample fallback (`sample_map.cpp`) and the processor's Tier-0 fallback that
  consumed it — an empty stored selection resolves to **silence**, not sample #1. The
  editor draws a clear **empty state** ("pick a capture" affordance) when nothing is
  selected. Pure change is testable (empty id → `nullopt`); the empty-state draw is shell.
- [ ] Capture browser (pure layout + shell draw): grow `SampleChoice` to carry the
  **peak thumbnail data** (from the `Sample` peaks bank_model already stores — the same
  peaks the dock panel draws), the **root/key badge** (S2 `rootNote` intrinsic / the
  optional musical key), and its bank. A new pure `capture_browser` module lays out
  scannable **cards/rows** (card rect grid, thumbnail rect, hit-test a point → card) — no
  host types at the boundary, unit-tested. The shell draws each card's peak thumbnail +
  name + badge in LICE (house palette) and routes a click to select.
- [ ] Bank filter (pure + shell): a filter/tab strip over the browser that narrows the
  drawn cards to a chosen bank_book bank (or "all"). Filter-tab layout + hit-test pure
  (mirror of `mode_switch`); the active-filter state is transient UI state; the shell draws
  the tabs and applies the filter to the card list. (Type-to-filter search folds in from
  S12 — see S12's boundary note; a name-substring filter over the same card list.)
- [ ] Guided single-capture setup (the fast path): once a capture is picked, a prominent,
  self-explanatory setup surface — **root note** (settable on the keyboard strip / typed),
  **play-mode basics**, **level** — sized for the single-capture case, not a zone table.
  Graphic and descriptive; the point is to get from pick → set → play with no hunting.
- [ ] Pure `keyboard_strip` geometry module (serves the single-capture case first): map a
  MIDI key span across a strip width (128 keys → pixels, reusing the S6 `embed_strip`
  key-span idiom); a **root marker** for the loaded capture; `pixel→note` and a `keyAtPoint`
  for click-to-set-root; a drag-delta resolver `(grabbedField, startNote, dxPixels) →
  newNote`; **per-zone bar rect** + **edge-grab hit regions** (resize handles vs. body
  move-handle) for the opt-in Zones panel. No VST3/REAPER/LICE types at the boundary;
  unit-tested (root marker, edge grabs, body-move delta, key mapping, clamps low≤high,
  boundary rounding). Mirror of `mode_switch`/`editor_geometry`.
- [ ] Editor shell drag-state machine: `WM_LBUTTONDOWN` grabs a card / a key / a zone
  edge-or-body, `WM_MOUSEMOVE` updates the in-flight edit against the pure resolver,
  `WM_LBUTTONUP` commits via the existing `commitMapAndReload` (off-thread reload; RT path
  untouched). Live visual feedback while dragging; a single undo-coherent edit on release.

### S10-Z — Zones panel (opt-in multi-zone keymap editing; demoted from the default face)
The multi-zone keymap editor is now an **opt-in view/panel** ("Zones" toggle), not the
default. It reuses the same `keyboard_strip` geometry and drag-state machine: each zone a
bar over the keys it covers; **drag an edge** → low/high note; **drag the bar body** → move
the zone (span preserved); **click a key** → set/relocate the zone's root. This is the
capability RS5K structurally lacks (multi-zone in one instrument), kept as a *nice-to-have*
per Daniel's hierarchy — "most of the time the zones won't be used." Add/select/delete a
zone; overlapping zones render legibly and resolve first-match. The seven ±1 nudge/delete
mini-buttons are retired everywhere; delete is one affordance (a small × on the bar or a
keystroke). The `zoneHitTest`/±1 nudge path in `editor_geometry` is retired (a numeric
fallback for accessibility is a build-time residual, not a fork).
**Verify (in DAW):** the Zones panel is reachable via an explicit toggle (default view is
the capture browser + single-capture setup, not this); a zone's range is set by **dragging
edges** (not nudge clicks); body-drag moves the span; click-a-key sets the root (audible on
the next held note); zone add/select/delete work; the ±1 nudge row is gone.

- [ ] "Zones" panel toggle (opt-in): the default editor face is the capture browser +
  single-capture setup; a toggle reveals the multi-zone keymap editor. Toggle state is
  transient UI state (or per-instance component state if it should persist — build-time
  residual).
- [ ] Zone edit via the shared strip: draw the keyboard strip + zone bars in LICE, drive
  the shared drag-state machine (edge = resize, body = move, key = root), commit via
  `commitMapAndReload`. Zone add/select/delete as single affordances; ±1 nudge row gone.

---

## S11 — waveform view with draggable loop points (UX overhaul, part 2)
**Goal:** Give each sample/zone a **waveform display** with **draggable start/end/loop
markers** — the S2 loop-point intrinsics and the S5 performance map already carry the data;
today there is no way to *see* a sample or *set* its loop by eye. Selecting a zone (or a
bank sample) shows its waveform (peaks via the existing `peaks` module, fed the decoded
PCM the shell already loads); drag the **loop-start / loop-end** markers to set the sustain
loop, snapping to zero-crossings (the S2 spec's zero-crossing-aware requirement). Loop
points are a **performance-map override on the zone** where set, seeded from the bank
intrinsic (D-B split: the bank carries the file-fact default; the instrument's drag is the
performance choice). All marker/waveform layout + hit-test is pure geometry; peaks compute
reuses `peaks`; the draw + drag is the shell. CONTEXT.md §Phase S (ReaSampler 9000 UX —
waveform view).
**Verify (in DAW):** selecting a zone shows its sample's waveform; dragging the loop-start
and loop-end markers sets the sustain loop and a held note audibly loops that region;
markers snap to the nearest zero-crossing; a sample with no loop shows the "no loop" state
and a held note past the end goes silent (existing core behavior); the waveform peaks match
the audio (mirror of the `peaks` envelope assertion); the marker geometry module is
CTest-green (px↔frame mapping, marker grab regions, clamp start≤end).
**Depends on:** S2 (loop-point intrinsics), S3 (loop-aware sustain the markers drive), S5
(the zone the loop attaches to), S10 (shares the editor's drag-state machine + shell). The
zero-crossing snap is a small pure helper over the decoded PCM.

> **Boundary note (S10 reframe, 2026-07-26):** the waveform view is now **central to the
> single-capture fast path**, not just per-zone. Selecting a capture in S10's browser shows
> its waveform (this is "see it" in pick → see it → play it); the loop-marker drag here
> extends that same waveform surface. S11's waveform draw is the same one S10's picked-
> capture view uses — build it once, S10 shows it read-only for the single capture, S11 adds
> the draggable loop markers. No renumber; S11 stays the loop-editing point.

- [ ] Pure waveform/marker geometry: `frame↔pixel` mapping across the waveform rect, marker
  x-position from a frame index, marker grab regions (start/end/loop-start/loop-end),
  drag-delta `(grabbedMarker, dxPixels) → newFrame` with clamps (start≤end, in-bounds). A
  **zero-crossing snap** helper: nearest sign-change frame to a target (pure, over the
  decoded mono PCM). No host types; unit-tested.
- [ ] Waveform draw: compute peaks with the existing `peaks` module from the shell's already-
  decoded PCM (no new decode path, no new WAV reader); draw the envelope in LICE in the
  house style; draw the loop markers over it. Reuses the S10 drag-state machine.
- [ ] Loop-point edit → performance-map override: a dragged loop writes a per-zone loop
  override (seeded from the S2 bank intrinsic, D-B), committed off-thread via
  `commitMapAndReload`; the bank intrinsic is never written back (instrument is a read-only
  bank consumer). Extends `PerformanceZone` with an optional loop override (additive, same
  shape as `rootOverride`) + its component-state (de)serialize (version bump, back-compat
  with S5's v2 map blob — a truncated/older blob defaults the override absent).

---

## S12 — editor scale + ergonomics (UX overhaul, part 3; scrollable/searchable list, direct entry)
**Goal:** Make the editor usable **at bank scale** and close the remaining RS5K-parity
gaps: the sample list **scrolls** (today a long bank's rows run off the panel with no way
to reach them) and has a **type-to-filter search**; add **direct numeric entry** for a
zone's low/high/root (a click-to-type field over the strip, for precision the drag can't
hit) and an **ADSR control** for the amp envelope (S3 already has the ADSR math; today it
is fixed — expose attack/decay/sustain/release as draggable sliders, per-instance state).
This is the "sensible list handling + direct manipulation of the parameters that exist"
tier. All slider/scroll/search-box layout + hit-test is pure geometry; the shell draws +
routes; ADSR/scroll/filter state is instrument-owned (component state / transient UI
state). CONTEXT.md §Phase S (ReaSampler 9000 UX — scale + ergonomics).
**Verify (in DAW):** a bank with more samples than fit **scrolls** (wheel + drag) and every
sample is reachable; typing filters the list to matching names; a zone's low/high/root can
be **typed** (not only dragged) via a click-to-edit field; the amp envelope's ADSR is
**adjustable** (four draggable controls) and the change is audible + persists across project
save/reopen (component state); the scroll/search/slider geometry is CTest-green.
**Depends on:** S10 (the editor shell + drag-state machine + the **capture browser** the
scroll/search now apply to), S3 (the `AdsrParams` the ADSR sliders drive — already wired
into the voice engine; today they are fixed defaults), S5 (the map the numeric fields edit).

> **Boundary note (S10 reframe, 2026-07-26):** the "sample list" S12 originally scrolled and
> searched **is now S10's capture browser** (cards with peak thumbnails, bank filter). What
> pulled INTO S10: the browser layout itself, the peak thumbnails, and the **bank filter**
> (a bank_book tab, distinct from name search). What stays in S12 and applies **to S10's
> browser**: (a) **scroll** for a bank longer than the panel, and (b) **type-to-filter
> search** (a name-substring narrow over the same cards, composing with S10's bank filter —
> bank filter picks the bank, search narrows within it). The scroll/search geometry is pure,
> layered over the `capture_browser` module S10 builds. Net: S12 = scroll + search over the
> S10 browser + numeric entry + ADSR; the browser *card* work is S10's. **S12 now also
> carries the S15/S16 control surfaces** (per-zone Gate/Trigger mode toggle, AHDSR hold
> control, Trigger %-length/fade controls, Varispeed/Preserve engine toggle, and the AD pitch
> envelope depth/shape controls) — deferred here from S15 and S16 per spec.

- [x] Scrollable, searchable capture browser: a scroll offset (wheel + scrollbar drag) so a
  bank longer than the panel is fully reachable; a **type-to-filter search** that narrows
  the drawn cards to matching display names, **composing with S10's bank filter** (bank
  filter selects the bank; search narrows within it). Scroll/search layout + hit-test is
  pure geometry (visible-card window, scrollbar thumb rect, search-box rect), layered over
  S10's `capture_browser` module; filter/scroll state is transient UI state. **Landed:**
  pure `browser_scroll` module (`browser_scroll_tests`) — scrollContentHeight / max / clamp,
  visibleCardRange window, scrolledCardCellRect, scrollThumbRect + thumbDragToOffset inverse,
  searchBoxRect, nameMatchesQuery + filterNameIndices. Editor shell wires wheel (`WM_MOUSEWHEEL`),
  thumb-drag (`DragKind::kScrollThumb`), and the search box (`WM_CHAR` -> `onSearchChar`,
  composed into `rebuildVisible`). Scroll/search are transient (never persisted).
- [x] Direct numeric entry for zone low/high/root: a click-to-edit field over the strip
  (LICE text-entry idiom) so a precise note can be typed, not only dragged. Commits via
  `commitAndReload` like every other edit. **Landed:** pure `note_entry` module
  (`note_entry_tests`) — `parseNoteEntry` accepts a decimal integer OR a note name (C4==60),
  clamps to [0,127], rejects garbage. Editor shell hosts three focusable fields (low/high/root)
  on the Zones legend, committing on Enter through `commitAndReload`.
- [x] ADSR/AHDSR editor + S15/S16 control surfaces: draggable sliders over the S3 `AdsrParams`
  (attack/**hold**/decay/sustain/release — hold is the S15 addition) plus the deferred S15/S16
  controls — per-zone Gate|Trigger mode toggle, Trigger %-length/fade-in/fade-out, Varispeed|
  Preserve engine toggle, and the AD pitch-envelope enable/attack/decay/±semitone depth. All
  edit the SELECTED zone's `ZonePlayParams` (instrument-owned, D-B; never the bank), round-trip
  through the existing v3 component-state blob (no new persistence — the S15/S16 payload already
  landed in the core pass), and commit off-thread via `commitAndReload`. **Landed:** pure
  `param_slider` module (`param_slider_tests`) — control-panel stack layout, toggle-segment
  split + hit-test, slider value<->pixel round-trip + clamping, point->control routing. The
  shell owns the control-id -> engine-param binding + the value DOMAIN mapping (frames/fraction/
  semitones); the module stays engine-free.

**Notes/decisions:**
- **Wall-clock envelope times stored as rate-free SECONDS (zones payload v5)**, resolved to
  frames at keymap build against the live project rate — no hardcoded sample rates anywhere in
  `src/`. Daniel's standing ruling; enforced throughout the voice engine and verified at S12.

---

## S13 — drop-to-load (partial landing; relay deferred)
**Goal:** Make "load a sample into the sampler" **one gesture from the editor** via an
OS file drop onto the editor window. The cross-artifact relay was a spike — the
instrument's REAPER bridge (`reaper_bridge`) is deliberately READ-ONLY; the relay is
DEGRADED and deferred. The two landed items are the drop-accept surface and the UX degrade
path. The deferred relay item remains in `PLAN.md`. CONTEXT.md §Phase S (drop-to-load).

**Spike verdict (ps-w12, 2026-07-27): DEGRADED.** The relay would require (a) a new
instrument WRITE seam into ext-state and (b) an extension-side timer poller + claim/clear
nonce — the same cross-process handshake race the S17 spec rejected. The shipped ingest
gesture stays drop-onto-docked-panel (S8). The relay is a future wave when the design is
ready.

- [x] Editor-window drop target: accept `WM_DROPFILES`/`IDropTarget` on the editor child
  HWND (the same SWELL/Win32 surface `bank_panel` owns), extracting the dropped file
  path(s). Windows-only (D5). This is the *acceptance* half; the ingest is the extension's.
  **Landed:** the editor child window calls `DragAcceptFiles(TRUE)` on attach and handles
  `WM_DROPFILES` (`reasampler_editor.cpp`). Windows-only (D5).
- [ ] Cross-artifact ingest relay (the S8-flagged spike): **DEFERRED** — relay mechanism
  proved load-bearing to redesign. Remains in `PLAN.md` §S13.
- [x] UX degrade path: when the relay is unavailable/unproven, the editor shows a clear
  "drop files on the ReaSampler panel to add" affordance rather than silently swallowing the
  drop — the shipped ingest gesture stays discoverable either way. **Landed:** the editor
  ACCEPTS the drop and flashes a transient banner ("drop files onto the ReaSampler bank panel
  to add them") that decays over a few sync ticks, plus a persistent affordance line in the
  empty state ("drop a file onto the ReaSampler bank panel"). No file is ingested; NO timeline
  item is ever inserted (the hard invariant — the editor only displays guidance).

---

## S15 — sampling modes: Trigger vs Gate (per-sample play-mode; core + editor)
**Goal:** Give each played sample a **play mode** — **Gate** (classic held note) or
**Trigger** (one-shot) — a per-sample/per-zone performance choice (D-B, instrument-owned).
**Gate** is today's behavior grown from ADSR to **AHDSR** (adds a Hold stage): note-on →
attack/hold/decay/sustain, note-off → release, sustain **loop points apply** (S11's
draggable loop UI is Gate-mode UI). **Trigger** is a one-shot drum-pad: note-on fires
playback of a defined **% of sample length** with a **fade-in** and **fade-out** ramp,
**ignores note-off**, and uses **no sustain loop**. **Both** modes carry a **modifiable
start point** (playback begins at an offset into the sample, not always frame 0). This is
an **S3-core extension** (the engine Daniel smoke-tests) plus editor surfacing — the mode +
its parameters are instrument performance-map state, never a bank fact. CONTEXT.md §Phase S
(Sampling modes — Trigger vs Gate). **Daniel's feature set is settled.**
**Verify (in DAW):** a sample in **Gate** mode plays held with the AHDSR envelope (hold
stage audible between attack and decay), releases on note-off, and loops its sustain region
if loop points are set; a sample in **Trigger** mode fires a fixed % of its length on
note-on with audible fade-in/out, **plays through to completion regardless of note-off**,
and never sustain-loops; the **start point** offsets playback in both modes (a note starts
partway into the sample); the mode + parameters are per-instance component state that
survive save/reopen; the pure core's Trigger envelope (fade-in → hold → fade-out over
%-length frames) and the AHDSR hold stage are asserted against known signals; existing
Gate/ADSR behavior is unchanged when hold=0 (regression).
**Depends on:** S3 (extends the envelope + voice read-position machinery), S5 (the
`PerformanceZone` the mode + params attach to), S11 (Gate loop-point UI; Trigger's waveform
shows start + %-length + fades on the same waveform surface). Independent of S7.

- [x] Core: `PlayMode { Gate, Trigger }` on the voice + the envelope split. **Gate** grows
  `AdsrParams` → `AhdsrParams` (add `holdFrames` between attack and decay; hold=0 is the
  exact current ADSR — back-compat). **Trigger** is a distinct envelope: play `[start,
  start + lengthFraction·(frames−start))` with a **fade-in** ramp (0→1 over `fadeInFrames`)
  and a **fade-out** ramp (1→0 over `fadeOutFrames` ending at the play-length end),
  **ignoring note-off** (release is a no-op in Trigger). Fade curve default **equal-power**
  (constant-power `sin`/`cos`, click-free on one-shots); pure, unit-tested against a known
  signal.
- [x] Core: **modifiable start point** — the voice's initial `readPos_` is `startFrame`
  (frame offset), applied in both modes; the existing per-frame `readPos_ += ratio_` read
  and loop/interp machinery is otherwise unchanged. Clamp `0 ≤ startFrame < frames`.
- [x] Core: **% length → frames + fade mapping** for Trigger. `lengthFraction ∈ (0,1]`
  resolves to `playEnd = start + round(lengthFraction·(frames − start))`; `fadeInFrames` /
  `fadeOutFrames` clamp so their sum ≤ play length (fade-out anchored to `playEnd`). Note-off
  in Trigger does nothing; the voice frees when `readPos_ ≥ playEnd`. **Choke on note-off is
  NOT in scope** (fork S15-F1, held).
- [x] Parameter ownership (per-sample/per-zone, instrument-owned): the play mode + its
  params (Gate: AHDSR; Trigger: %-length, fade-in, fade-out; both: start point) attach to
  the **capture selection / zone**, stored in the **performance map** (D-B). Additive/
  version-bumped component state; back-compat — a truncated/older blob defaults to **Gate**,
  hold=0, start=0, no fades = exactly today's behavior.
- [x] Editor (S11 waveform surface, mode-aware): **Gate** shows draggable **start + loop
  markers** (S11's loop UI); **Trigger** shows **start + %-length end + fade-in/out**
  handles on the same waveform. A **mode toggle** per capture/zone in the guided setup
  (S10) / Zones panel (S10-Z). Marker/handle geometry is pure; commits off-thread via
  `commitMapAndReload`. The instrument stays a **read-only bank consumer**. **Editor control
  surface deferred to S12 tier (spec-sanctioned).**

---

## S16 — pitch engine modes (Varispeed vs Preserve) + pitch envelope (per-voice)
**Goal:** Give the sampler **two pitch behaviors** and a pitch envelope that rides whichever
is chosen. **Varispeed** — resampling that couples pitch and duration (classic sampler /
RS5K default). **Preserve** — duration-preserving repitch, where a transposed note keeps
its original length. A **per-zone/per-capture pitch-engine mode**. On top of either engine
rides a per-voice **AD pitch envelope**, **off by default** — a short attack-decay pitch
modulation. Per-instance performance-map state (D-B). CONTEXT.md §Phase S (Pitch engine
modes + pitch envelope).
**Verify (in DAW):** Varispeed — a note an octave up plays half as long as the root note;
Preserve — a note an octave up plays at the same duration as the root note; pitch envelope
off (default) under either engine: no pitch modulation applied (regression); pitch envelope
on: an AD envelope makes a note start offset in pitch and glide to the zone's base pitch
over attack+decay; CPU stays within budget at polyphony cap.
**Depends on:** S3, S5, S15. Independent of S7.

- [x] Core: **pitch-engine mode on the voice/zone** — `PitchEngine { Varispeed, Preserve }`.
  **Varispeed** = `readPos_ += ratio_` (today's path, pitch and duration coupled). **Preserve**
  = duration-preserving: the read advances at the **source** rate while a pitch shifter
  transposes the output. Mode is per-`PerformanceZone` performance state (D-B), additive/
  version-bumped; absent/older blob → engine default. Pure where possible: Varispeed math and
  duration-invariance contract unit-tested.
- [x] Core: **Preserve engine implementation** — hand-rolled pure OLA `pitch_shift` module
  (house pattern — CTest-testable, no WDL/REAPER/VST3 type at the boundary). Pre-allocated,
  no locks, no `process` allocation; pre-warmed at voice allocation. `pitch_shift_tests`
  CTest target. WDL_SimplePitchShifter excluded by include-chain (windows.h); held as a
  quality/latency swap alternative (`PitchEngine::Preserve` contract identical behind the seam).
- [x] Core: a per-voice **AD pitch envelope**, engine-aware — `PitchEnvParams { enabled=false,
  int64 attackFrames, int64 decayFrames, double peakSemitones }`. Off by default (`enabled=false`
  → offset always 0). Under **Varispeed** the offset multiplies `ratio_`; under **Preserve**
  the offset is **added to the shifter's shift amount**. Pure, unit-tested.
- [x] Parameter ownership + editor: pitch-engine mode + pitch envelope are per-zone
  instrument performance-map state (D-B), additive/version-bumped. Editor exposure deferred
  to S12 tier (spec-sanctioned). The instrument stays a **read-only bank consumer**.

**Notes/decisions:**
- **S16-F1 (default engine):** default is **Preserve** (Daniel's directive: "I want
  duration-preserving repitching"). Per-zone toggle prominent and cheap to flip for
  drum/one-shot zones that want Varispeed character.
- **S16-F2 (Preserve engine):** hand-rolled pure OLA `pitch_shift` module chosen over
  `WDL_SimplePitchShifter` (excluded by include-chain). Both share the same
  `PitchEngine::Preserve` contract; `WDL_SimplePitchShifter` is held as the quality/latency
  swap (the HELD item in `PLAN.md`).

---

## S17 — drop-and-load: drag a capture onto a track's FX button → instantiate ReaSampler 9000 with the capture loaded
**Goal:** Turn a bank capture into a playable instrument in one gesture. While a capture
is dragged from the `bank_panel`, a track's TCP **FX button** lights as a drop zone,
and dropping there instantiates a **ReaSampler 9000** on that track with the dragged
capture **already loaded and selected** for playback. A third `DragGesture` —
`InstrumentDrop` — added to the `drag_out` pure module. Mechanism: `TrackFX_AddByName` +
VST3 component-state injection via `TrackFX_SetNamedConfigParm(..., "vst_chunk", blob)`.
The shared `instrument_drop` pure module constructs the blob via the instrument's own
`sample_map::serializeComponentState`/`deserializeComponentState` — one serializer called
from both artifacts, so the blob format cannot drift. CONTEXT.md §Phase S (drop-and-load).
**Verify (in DAW):** dragging a single capture from the dock over a track's FX button
highlights it; dropping instantiates ReaSampler 9000 on that track with the dragged
capture loaded, selected, and MIDI-playable immediately; OS drag-out to Explorer still works
unchanged; internal bank-to-bank drag still works unchanged; no media item ever inserted
into the arrange. DAW-verify: whether REAPER's `vst_chunk` write-parm expects the plugin's
raw IComponent-state bytes or wraps them in a REAPER container header.
**Depends on:** M11 (`drag_out` gesture machinery), Phase S S4, the load-capture seam
(VST3 component-state injection — the shared blob contract).

- [x] Extend the `drag_out` pure module with the third gesture: `DragGesture::InstrumentDrop`
  when a drag armed with a **single** capture is over REAPER's UI outside the panel client
  rect; `OsDrag` only when it has left REAPER entirely; `Internal`/`OsDrag`/`None` otherwise
  unchanged. `DragState` gains two defaulted fields (`singleCapture`, `overReaperUi`); M11
  callers filling only `{dragging, hasArmedSamples}` get byte-identical M11 behavior — the
  existing tests are the non-regression proof. **OPEN QUESTION RESOLVED (multi-capture over
  FX button): REJECT** — only `singleCapture` arms InstrumentDrop; multi-payload over
  REAPER UI falls through to `OsDrag`.
- [x] Shell (extension): hover-track the pointer over REAPER's UI during the drag; resolve
  the hovered track + its FX button via `GetThingFromPoint` (verified present; its info string
  reports `"fx_chain"`/`"fx_N"` for the FX region); highlight it as a drop target; on release
  drive the drop. FX HOTSPOT resolved — drop target is the FX region (info prefix `"fx_"`),
  not home-grown geometry. `instrument_drop_win::resolveFxDropTarget` implements this.
  **Landed in `src/instrument_drop_win.cpp`.**
- [x] Shell (extension): on drop, `TrackFX_AddByName(track, "VST3:" + app_version::vstPluginName(),
  false, negative)` to always add a fresh instance; capture the returned FX index; invoke the
  load-capture seam. Batched into one REAPER undo point (`Undo_BeginBlock2`/`EndBlock2`).
  NEVER inserts a timeline item. **Landed: `instrument_drop_win::performInstrumentDrop`.**
- [x] **ReaSampler 9000 load-capture seam:** the instrument's existing `setState`/`getState`
  already round-trip the full `ComponentState` via
  `sample_map::serializeComponentState`/`deserializeComponentState` (S10). The extension
  REUSES that exact serializer through the new pure `instrument_drop` module
  (`buildInstrumentDropChunk` → `serializeComponentState` → base64). The shared-writer
  requirement is met STRUCTURALLY — the blob format cannot drift. Pure round-trip test decodes
  back through the instrument's own reader and asserts the capture is selected.
  **`instrument_drop` lives at `src/instrument_drop.{h,cpp}`** (extension-side pure module);
  CTest target `instrument_drop_tests`.
- [x] Tests: gesture disambiguation (inside-panel / over-REAPER-UI / left-REAPER) across
  single- and multi-capture payloads; M11 OS drag-out and internal bank-to-bank drag both
  unchanged. `test_drag_out.cpp` adds the InstrumentDrop cases with M11 cases retained as
  the non-regression guard; `test_instrument_drop.cpp` is the blob round-trip + base64 codec
  coverage. FX hit resolution is REAPER-API-bound (`GetThingFromPoint`) — DAW-verified in the
  shell, not pure-tested (noted honestly).

**Notes/decisions:**
- `resetDragState()` consolidation in `bank_panel` (prior drift cleaned up this wave).
- Copy-only / no-auto-insert / no-source-deletion invariants all hold: NEVER inserts a
  timeline item; the bank file is not deleted; prune remains the sole file-deleter.

---

## S18 — VST3 channel isolation: a beta ReaSampler 9000 that pairs with the beta extension only
**Goal:** Extend Phase V's beta/stable channel split (V4) to the **ReaSampler 9000 VST3
instrument**, so a beta-built VST is a distinct plugin that pairs only with the beta
extension, and a stable VST pairs only with stable — installable side-by-side in one REAPER
with no collision. **One channel per binary; all identity derives from the ONE
`REASAMPLER_CHANNEL_IS_BETA` bit via `app_version`, no scattered `#ifdef`s.** Mirrors V4's
philosophy exactly. Two forever-stable VST3 class UIDs committed (the existing stable UID +
a new beta UID). CONTEXT.md §Phase S (VST3 channel identity — the UID-pair invariant).
**Verify (in DAW):** stable VST3 (`reasampler_9000.vst3`) and beta VST3
(`reasampler_9000_beta.vst3`) install side-by-side in one REAPER as distinct plugins;
a beta instance reads only the beta extension's banks; a stable instance reads only stable's;
save/reopen rebinds by the correct UID; nothing plays differently (identity/pairing wave only).
**Depends on:** V4 (`app_version` channel-identity single-source), S1 (VST3 factory identity).

- [x] **Beta VST3 class UID (the permanent commitment).** Second FOREVER-STABLE class UID
  (`REASAMPLER_PROC_UID_BETA_1..4` + `kReaSamplerProcessorUIDBeta`) alongside the existing
  stable UID in `reasampler_vst.h`. The channel bit selects which UID the factory registers
  (`DEF_CLASS2`) — compile-time, one class per binary. Both UIDs frozen forever.
- [x] **Channel-derived binary + display identity (no scattered `#ifdef`s).** Binary name:
  CMake VST3 target `OUTPUT_NAME` forks by channel — `reasampler_9000` (stable) /
  `reasampler_9000_beta` (beta) — via `REASAMPLER_VST_OUTPUT_NAME`. Display name: factory
  `DEF_CLASS2` plug-in display string sourced from `app_version::vstPluginName()` — "ReaSampler
  9000" / "ReaSampler 9000 beta". Editor title band + S6 embed-strip label channel-aware from
  the same accessor.
- [x] **Factory vendor/version strings channel-aware** where V4 does the equivalent. Version
  display carries the `-beta` render (`appVersion()` yields `"0.9.01-beta"` on beta).
- [x] **Pairing-surface invariant recorded** (no new code — a documented guarantee): channel
  isolation is structural — all wire keys live under the channel-derived `kProjExtNamespace()`,
  so a future wire key that forgets to isolate is impossible by construction. The invariant
  is recorded in CONTEXT.md.
- [x] **DAW-verify contract (the acceptance gate, no unit test — identity is a shell fact).**
  Both channels installed side-by-side: each browser sees only its channel's banks; a
  project saved with a beta instance reopens rebinding to the beta VST and restores its state.
