docs: archive Phase R (R1-R3) to COMPLETED; reconcile CLAUDE.md + CONTEXT.md

CLAUDE.md

@@ -4,7 +4,7 @@ This file provides guidance to Claude Code (claude.ai/code) when working with co
 
 ## Repo identity and current state
 
-The CMake project and binary are now named `reaper_reasampler`. This is **ReaSampler** — a per-project audio sample-bank capture tool. The MPE modules (`mpe_model`, `mpe_view`) have been removed. M0–M8 are complete (bank_model, peaks, capture offline+realtime, persist, bank_panel, insert, capture action family, RealtimeRecordBackend, tail T1+T2+T1-followons). Phase B multi-bank (B1–B5, B-cap), Phase D1/D2 Design View (D1–D5, D2-W1–W3-B), Phase V versioning/beta-channel (V1/V3, V4), and M10 provenance + re-capture from source have all landed. M9 slots, M11 polish, and Phase R prune remain. The *discipline* — pure REAPER-free testable core split from REAPER-facing shells — is **preserved** throughout.
+The CMake project and binary are now named `reaper_reasampler`. This is **ReaSampler** — a per-project audio sample-bank capture tool. The MPE modules (`mpe_model`, `mpe_view`) have been removed. M0–M8 are complete (bank_model, peaks, capture offline+realtime, persist, bank_panel, insert, capture action family, RealtimeRecordBackend, tail T1+T2+T1-followons). Phase B multi-bank (B1–B5, B-cap), Phase D1/D2 Design View (D1–D5, D2-W1–W3-B), Phase V versioning/beta-channel (V1/V3, V4), M10 provenance + re-capture from source, and Phase R Reclaim (R1–R3: prune-reconcile core, dry-run shell, guarded deletion + action + panel button) have all landed. M9 slots and M11 polish remain. The *discipline* — pure REAPER-free testable core split from REAPER-facing shells — is **preserved** throughout.
 
 CONTEXT.md is the authoritative spec and build roadmap. Read it first for any non-trivial task. Every REAPER API name cited there is correct-by-intent; verify argument order, types, and flag values against `vendor/reaper-sdk/sdk/reaper_plugin_functions.h` before use.
 
@@ -37,6 +37,8 @@ Key targets (see CMakeLists.txt for the full list):
 | `owned_manifest_tests` | executable | Pure unit tests for `owned_manifest` — no REAPER, no DAW. |
 | `app_version_tests` | executable | Pure unit tests for `app_version` — no REAPER, no DAW. |
 | `provenance_tests` | executable | Pure unit tests for `provenance` — no REAPER, no DAW. |
+| `prune_reconcile_tests` | executable | Pure unit tests for `prune_reconcile` — no REAPER, no DAW. |
+| `prune_button_tests` | executable | Pure unit tests for `prune_button` — no REAPER, no DAW. |
 | `reaper_reasampler` | loadable module | The actual extension binary (`.dll` / `.dylib` / `.so`). |
 
 ### Beta channel build (Phase V, V4)
@@ -73,16 +75,18 @@ There is no hot-reload. Copy the built binary into REAPER's `UserPlugins/` folde
 - `app_version` — REAPER-free version/channel identity (Phase V, V1+V4): CMake-sourced semver constant (`appVersion()`), ext-state stamp value (`stampVersion()` — numeric triple only, no channel suffix), `parseVersion`/`versionLess`/`classifyWritingVersion`, and the full set of channel-derived identity accessors (`extStateNamespace()`, `commandIdPrefix()`, `actionDisplayPrefix()`, `binaryName()`, `dockTitle()`, `dockIdent()`, `channelCommandId()`, `channelActionName()`). All channel strings derive from the one `REASAMPLER_CHANNEL_IS_BETA` bit threaded in via `configure_file` → `version_generated.h`; no scattered `#ifdef`s in the shells.
 - `wav_trim` — 32-bit-float WAV parse + header-aware truncate plan (RIFF/data size rewrite) for the realtime tail's PCM decay-scan trim (T2). Rejects WAVE_FORMAT_EXTENSIBLE with non-float SubFormat GUID. Depends on `peaks` for the `AudioSample` float alias.
 - `provenance` — capture-recipe fingerprint (M10): build/encode/compare a `rsprov1` length-prefixed fingerprint of scope, exact range, tail, rate/channels, track GUIDs, and order-sensitive FX-chain identity; parse/compare for drift detection on re-capture. A thin reproducibility fingerprint — NOT a serialized chain to restore. Drives `BankIndex::updateInPlace` / `BankBook::updateSampleInPlace` (order-preserving, id-stable) on re-capture.
+- `prune_reconcile` — Phase R pure prune core: `pruneOrphans(present, referenced, owned)` computes `(owned ∩ present) − referenced` (exact-string path match); `buildPruneReport` tallies count/bytes/display-capped file list; `pruneDeletePlan` produces the confirm-time staleness intersection (`confirmed ∩ freshOrphans`). REAPER-free, filesystem-free. The safety-critical "which files are orphans" decision — hard-tested here before any I/O exists. Also: `BankBook::referencedPaths()` additive const union query (all banks incl. pool, de-duped) added to `bank_book`.
+- `prune_button` — Phase R pure layout/hit-test for the `bank_panel` footer Prune button: `computePruneButton` (right-anchored, suppressed gracefully when footer is too narrow) + `hitTestPruneButton`. Mirror of `mode_switch` / `tab_strip`.
 
 **REAPER-facing shells:**
 - `capture` — `ICaptureBackend` interface; `OfflineRenderBackend` (deterministic default) and `RealtimeRecordBackend`. Input: `CaptureRequest`. Output: finished file + populated `Sample` handed to `bank_model`.
 - `insert` — placement via `InsertMedia`; conform-to-project-tempo is an explicit opt-in flag, never silent stretching.
 - `bank_panel` — docked LICE-drawn grid: thumbnails, audition, multi-select, keyboard navigation.
-- `persist` — project ext state (`SetProjExtState` / `GetProjExtState`, namespace `"reasampler"`) ↔ `BankBook` JSON (`"banks"` key) + `ViewModeModel` JSON (`"view_state"` key) + `TailSetting` JSON (`"tail_setting"` key) + `OwnedManifest` JSON (`"owned_files"` key) + writing-version stamp (`"version"` key, written via `stampVersion()` on every `saveToActiveProject()`); project-relative path resolution. A `projectconfig` hook (`BeginLoadProjectState(isUndo)`) triggers a deferred session reload on undo/redo so Ctrl-Z/redo visibly restores book/view/tail/manifest in-session.
+- `persist` — project ext state (`SetProjExtState` / `GetProjExtState`, namespace `"reasampler"`) ↔ `BankBook` JSON (`"banks"` key) + `ViewModeModel` JSON (`"view_state"` key) + `TailSetting` JSON (`"tail_setting"` key) + `OwnedManifest` JSON (`"owned_files"` key) + writing-version stamp (`"version"` key, written via `stampVersion()` on every `saveToActiveProject()`); project-relative path resolution. A `projectconfig` hook (`BeginLoadProjectState(isUndo)`) triggers a deferred session reload on undo/redo so Ctrl-Z/redo visibly restores book/view/tail/manifest in-session. Hosts `ReaSamplerSession::pruneDryRun()` (read-only orphan enumeration via M4 project-relative resolution) and `pruneOrphanSet()` (full-set query for the R3 delete path); supplies `referencedPaths()` + `owned().paths()` to the `prune_reconcile` pure core.
 - `view` — Design View shell: reads the folder tree via `view_tree`, snapshots flag values before parking, drives hide + CPU-park on inactive-mode leaves (`B_SHOWINTCP`/`B_SHOWINMIXER`/`B_MAINSEND`/`I_FXEN` + per-FX offline) and derived visibility on parents; restores from snapshot. Never touches master or `B_MUTE`/`I_SOLO`.
 - `track_guid` — shared `MediaTrack*` → canonical GUID-string formatter; single source of truth for membership keys used by both the view shell and the actions layer.
 - `provenance_shell` — FX-chain identity queries via `TrackFX_*` / `TakeFX_*` APIs; collects source-item paths and parent-detection inputs to feed the pure `provenance` fingerprint builder. Stamps `Sample.provenance` on capture when every resolving source item maps by exact normalized path (case-folded on Windows) to exactly one bank sample; ambiguous/mixed cases record nothing conservatively.
-- `actions` — registers the capture/placement/slot action family, the Design View action family (toggle active mode, activate Arrange/Design, tag/untag selected tracks, show-both), and the multi-bank action family (create/rename/reorder/delete bank, evacuate, activate, move/copy/remove selected samples); routes each to the modules above via the `command_id`/`gaccel`/`hookcommand` contract. Every bank index verb wraps its mutation in a batched REAPER undo point (`Undo_BeginBlock2`/`EndBlock2`, `UNDO_STATE_MISCCFG`) so one bank operation is one Ctrl-Z.
+- `actions` — registers the capture/placement/slot action family, the Design View action family (toggle active mode, activate Arrange/Design, tag/untag selected tracks, show-both), the multi-bank action family (create/rename/reorder/delete bank, evacuate, activate, move/copy/remove selected samples), and the Phase R prune action (`BANK_PRUNE_FOLDER` — dry-run-first, confirm-with-manifest, then `pruneDeletePlan`-guarded deletion; **the ONLY file-deletion authority in the system**); routes each to the modules above via the `command_id`/`gaccel`/`hookcommand` contract. Every bank index verb wraps its mutation in a batched REAPER undo point (`Undo_BeginBlock2`/`EndBlock2`, `UNDO_STATE_MISCCFG`) so one bank operation is one Ctrl-Z. The prune action writes no ext state and opens no undo point (file deletion is not REAPER-undoable).
 
 ## REAPER extension contract (src/main.cpp)