Docs: reflect Phase D1 landing

Rename view_model -> view_mode_model across Design View spec docs;
archive D1 to COMPLETED.md; add view_mode_model_tests to CLAUDE.md
targets table and pure-core list.

CLAUDE.md

@@ -22,13 +22,14 @@ Vendors two submodules (see `.gitmodules`):
     cmake --build build
     ctest --test-dir build
 
-Four targets:
+Five targets:
 
 | Target | Kind | Purpose |
 |---|---|---|
 | `bank_model_tests` | executable | Pure unit tests for `bank_model` — no REAPER, no DAW. |
 | `peaks_tests` | executable | Pure unit tests for `peaks` — no REAPER, no DAW. |
 | `capture_paths_tests` | executable | Pure unit tests for `capture_paths` — no REAPER, no DAW. |
+| `view_mode_model_tests` | executable | Pure unit tests for `view_mode_model` — no REAPER, no DAW. |
 | `reaper_reasampler` | loadable module | The actual extension binary (`.dll` / `.dylib` / `.so`). |
 
 ### macOS / Linux: SWELL dialog resources
@@ -48,6 +49,7 @@ There is no hot-reload. Copy the built binary into REAPER's `UserPlugins/` folde
 **Pure core (no REAPER types, unit-testable outside the DAW):**
 - `bank_model` — `Sample` metadata struct + `BankIndex` (add/remove/query/tier/dedup-by-hash + JSON round-trip). Test it hard — it is the heart.
 - `peaks` — waveform min/max bin computation from raw PCM. Fed a known signal, asserts envelope. Does not depend on REAPER's peak API.
+- `view_mode_model` — Design View mode system: mode registry, GUID-keyed membership, folder-tree-aware visibility derivation, snapshot-based park/restore planner, JSON round-trip. Mirror of `bank_model` for the Design View phase.
 
 **REAPER-facing shells:**
 - `capture` — `ICaptureBackend` interface; `OfflineRenderBackend` (deterministic default) and `RealtimeRecordBackend`. Input: `CaptureRequest`. Output: finished file + populated `Sample` handed to `bank_model`.

COMPLETED.md

@@ -115,3 +115,29 @@ folder still resolves the bank).
 - 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.
 - Known limitation (narrow, accepted): if a user does Save-As, closes the copy *without saving*, then reopens that copy to a *different* folder while the original is also open, identities can collide. Force-saving after Save-As would close the hole but was rejected as violating non-destructive.
+
+---
+
+## 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.

CONTEXT.md

@@ -239,7 +239,7 @@ the CPU reclaim; surface it at the toggle affordance (tooltip).
 ## Module architecture (preserve the pure/shell split)
 
 Pure (no REAPER types, unit-tested — the mirror of `bank_model`):
-- `view_model` — mode registry (id/name/ordinal; Arrange + Design seeded);
+- `view_mode_model` — mode registry (id/name/ordinal; Arrange + Design seeded);
   membership index (`track GUID → { mode ids }` + per-track show-both flag; add /
   remove / retag / query); **folder-tree-aware** visibility derivation (given the
   current parent↔child tree supplied by the shell + the active mode, compute the
@@ -250,7 +250,7 @@ Pure (no REAPER types, unit-tested — the mirror of `bank_model`):
 
 REAPER-facing:
 - `view` shell — reads `I_FOLDERDEPTH` across the track list to build the
-  parent↔child tree and feeds it to `view_model`; applies the planner's operations
+  parent↔child tree and feeds it to `view_mode_model`; applies the planner's operations
   via `SetMediaTrackInfo_Value` (`B_SHOWINTCP` / `B_SHOWINMIXER` / `B_MAINSEND` /
   `I_FXEN`) and `TrackFX_GetCount` + per-FX `TrackFX_SetOffline`; snapshots prior
   flag values before parking; resolves GUIDs via

PLAN.md

@@ -127,30 +127,6 @@ landed milestone.
 > spec: **CONTEXT.md §Design View**. Product framing: `docs/product/design-view.md`.
 > When a point lands, doc-keeper moves it to `COMPLETED.md`.
 
-## D1 — view_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.
-
-- [ ] Mode registry: ordered (id, display name, ordinal); Arrange + Design seeded;
-  add/query more modes (prove N-mode, not binary).
-- [ ] Membership index: `GUID → { mode ids }` + per-track show-both flag;
-  add / remove / retag / query; untagged = Arrange.
-- [ ] 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).
-- [ ] Parking/restore planner: emit exact (track, flag, value) op-lists for park and
-  restore from active mode + snapshot record.
-- [ ] JSON round-trip: modes + membership + show-both + snapshots + active mode.
-- [ ] 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).
@@ -159,7 +135,7 @@ CONTEXT.md §Design View (view shell, REAPER API surface).
 active ones from snapshot. **Master untouched. `B_MUTE`/`I_SOLO` untouched.**
 Untagged tracks untouched. Parents follow their tagged descendants.
 
-- [ ] Build parent↔child tree from `I_FOLDERDEPTH`; feed to `view_model`.
+- [ ] Build parent↔child tree from `I_FOLDERDEPTH`; feed to `view_mode_model`.
 - [ ] Snapshot prior flag values (`GetMediaTrackInfo_Value`) before parking.
 - [ ] Apply park/restore ops (`SetMediaTrackInfo_Value` for the four flags;
   `TrackFX_GetCount` + per-FX `TrackFX_SetOffline`). Verify flag names/signatures.

docs/product/design-view.md

@@ -273,7 +273,7 @@ index, and is togglable per selection.
 
 Mirrors the capture pillar's split exactly.
 
-**Pure `view_model` (REAPER-free, unit-tested — the mirror of `bank_model`):**
+**Pure `view_mode_model` (REAPER-free, unit-tested — the mirror of `bank_model`):**
 - Mode registry: ordered set of modes (id, display name, ordinal); Arrange + Design
   seeded; add/query more.
 - Membership index: `track GUID → { mode ids }` (normally one; multiple only via