docs: archive M11 completion (drag-out) to COMPLETED; reconcile CLAUDE.md

Native OS drag-out landed (copy-only, prune stays sole deleter).
Milestone 11 complete; M9 slots is the last M-numbered milestone.

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), M10 provenance + re-capture from source, Phase R Reclaim (R1–R3: prune-reconcile core, dry-run shell, guarded deletion + action + panel button), and M11 wave 1 (batch capture, action-button strip + keybinding labels, conform-on-insert verified-extant) have all landed. M9 slots and M11 native-OS-drag-out 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, Phase R Reclaim (R1–R3: prune-reconcile core, dry-run shell, guarded deletion + action + panel button), and M11 in full (batch capture, action-button strip + keybinding labels, conform-on-insert verified-extant, native OS drag-out) have all landed. M9 slots 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.
 
@@ -41,6 +41,7 @@ Key targets (see CMakeLists.txt for the full list):
 | `prune_button_tests` | executable | Pure unit tests for `prune_button` — no REAPER, no DAW. |
 | `batch_capture_tests` | executable | Pure unit tests for `batch_capture` — no REAPER, no DAW. |
 | `action_buttons_tests` | executable | Pure unit tests for `action_buttons` — no REAPER, no DAW. |
+| `drag_out_tests` | executable | Pure unit tests for `drag_out` — no REAPER, no DAW. |
 | `reaper_reasampler` | loadable module | The actual extension binary (`.dll` / `.dylib` / `.so`). |
 
 ### Beta channel build (Phase V, V4)
@@ -81,15 +82,17 @@ There is no hot-reload. Copy the built binary into REAPER's `UserPlugins/` folde
 - `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`.
 - `batch_capture` — M11 pure batch-capture planner: maps a list of source ranges to ordinal capture units, drives per-unit capture via a shared `captureAndIndexOne` helper, and aggregates mixed results. No REAPER types at the boundary.
 - `action_buttons` — M11 pure action-button strip layout/hit-test: divides a strip rect into N action buttons, min-width overflow-hiding, label formatting with "(unbound)" fallback, `ActionButtonRect` struct. Mirror of `mode_switch` / `bank_grid`.
+- `drag_out` — M11 pure OS drag-out 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.
 
 **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; a 28px action-button strip (M11) between the split body and tail footer that fires capture/insert/re-capture actions via `NamedCommandLookup` + `Main_OnCommand` and shows live keybinding labels via `kbd_getTextFromCmd`.
+- `bank_panel` — docked LICE-drawn grid: thumbnails, audition, multi-select, keyboard navigation; a 28px action-button strip (M11) between the split body and tail footer that fires capture/insert/re-capture actions via `NamedCommandLookup` + `Main_OnCommand` and shows live keybinding labels via `kbd_getTextFromCmd`; OS drag-out hook (M11) initiating an OS-level copy drag when the pointer leaves the panel client rect, via `drag_out` + `drag_out_win`.
 - `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.
+- `drag_out_win` — M11 OS drag-out shell: Windows OLE `DoDragDrop` / `CF_HDROP`, copy-only structurally (`DROPEFFECT_MOVE` not offered, no source-deletion path); macOS/Linux via `SWELL_InitiateDragDropOfFileList` (copy-semantics caveat documented — SWELL does not expose a drop-effect query). Driven by the `drag_out` pure module.
 - `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)