docs: retire the bake mono collapse and FX-GUID keying entries, file what they left behind

Both landed with accepted consequences rather than avoided ones, so COMPLETED
carries the identity move and the offline-FX degrade. Two line-ceiling entries
and the DAW-unverified GUID stability are now tracked.

docs/COMPLETED.md

@@ -1135,3 +1135,50 @@ exercises "the manifest parses, the layout computes, the exact-size proof fails"
 the payload boundary instead. No production module was touched — the wave adds test-tree
 files, the corpus, its README, the verification script, and one path variable in the root
 `CMakeLists.txt`.
+
+### Resample-bake mono collapse — closes the `docs/TODO.md` deferral (ad-hoc)
+
+`prepareLanding` (`src/shell/capture/bake_landing.cpp`) now applies the shared lossless
+mono collapse to the staged buffer — via a new thin wrapper `applyMonoCollapse` in
+`src/core/capture/wav_codec.cpp` — before the hash and the channel-count read, so the
+hash, the entry, and the written file all come from one collapsed buffer. A dead-center
+(dual-mono) bake now lands as a 1-channel file exactly as a dead-center offline capture
+already does; a true-stereo bake is byte-identical to before, asserted on bytes and on
+hash.
+
+**The blocker this deferral originally cited has cleared.** `bake_land.cpp` was
+another team's freshly-landed remediation surface at the time; that remediation has
+since landed, which is what made taking this item this wave safe.
+
+**Consequences accepted, not avoided:**
+- A dead-center bake's **content identity moves** — the hash now covers the collapsed
+  bytes, so a dual-mono bake will not hash-dedup against a stereo twin already in the
+  bank, and its derived file name changes. This was already documented as accepted for
+  the other capture paths in `src/core/capture/CLAUDE.md`; the bake path now inherits
+  it rather than being an exception.
+- `BakeOutcome::channelCount` now answers 1 for a dead-center bake, which flips the
+  instrument's channel-mode auto-default to Mono. Safe: the audio is identical either
+  way when the source was dead-center, and the consuming site was already written
+  anticipating that value.
+
+### Design View FX-GUID keying for `restoreFxOffline` — closes the `docs/TODO.md` deferral (ad-hoc)
+
+`restoreFxOffline` (`src/shell/view/view.cpp`) now returns each parked track's per-FX
+offline state to the plugin it was captured from, keyed by the FX's own GUID
+(`TrackFX_GetFXGUID`) rather than its slot index. New pure module
+`src/core/view/fx_offline.{h,cpp}` holds the keying types (`FxKeying`: Identity/Slot),
+the per-FX snapshot/plan types, and `resolveFxRestore`, which matches each captured
+state against the chain as it stands at restore time. `view_state` gained a v2 schema
+that writes the identity array beside the v1 slot array, so an older build reading a
+v2 blob keeps the behaviour it had rather than losing every FX state.
+
+**Consequences accepted, not avoided:**
+- A dropped FX (one whose captured identity is no longer live in the chain at restore
+  time) is left **offline**, as park left it, with its snapshot already cleared — the
+  console report names the drop and the recovery.
+- The console report uses the quiet `!SHOW:` form on every path, so it never
+  force-opens the console window.
+
+**Left open, filed to `docs/TODO.md`:** FX-GUID stability itself — whether
+`TrackFX_GetFXGUID` survives a chain reorder while parked — is unverified in the DAW
+(SWS issue #802 names a specific way it might not hold).