Docs: reconcile to two-scope capture model (master removed)

Update the CLAUDE.md FX-scope invariant to item+track only; note master
removal in COMPLETED.md; drop master references from the tail spec and PLAN
Milestone T; realtime now taps the selected track.

CLAUDE.md

@@ -85,4 +85,4 @@ There is no hot-reload. Copy the built binary into REAPER's `UserPlugins/` folde
 - **Non-destructive:** capture never mutates source items or tracks; the realtime backend's temp track is created and removed cleanly, and source routing is restored.
 - **Exact bounds:** no rounding of the requested range; no added silence unless a tail is explicitly requested; channel count preserved (no silent stereo fold).
 - **Relative paths only** in the persisted `BankIndex`.
-- **Capture FX scope:** item capture = item/take FX only; track capture = item + the track's own FX; master = full chain. For item/track, the out-of-scope chain (ancestors + master, plus the item's own track for item scope) is rendered with its FX, gain, and pan/width/pan-law/mode neutralized to unity — so captures are uncolored by, and independent of, the parent/folder/master chain. Range (time selection or razor) is orthogonal.
+- **Capture FX scope:** two scopes only — item = item/take FX only; track = item FX + the selected track's own track FX. There is no master scope (to capture the master, render a track instead). For both scopes, the out-of-scope chain (ancestors + master track, plus the item's own track for item scope) has its FX, gain, and pan/width/pan-law/mode neutralized to unity — the master track is bypassed as out-of-scope chain, not captured as a scope. Range (time selection or razor) is orthogonal.

COMPLETED.md

@@ -281,5 +281,6 @@ auto-inserts into the arrange.
 
 **Superseded / reworked (post-landing):**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:** 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.
+- **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.

PLAN.md

@@ -142,12 +142,12 @@ then trims at the -72 dB decay point (± inherent realtime tolerance); realtime
   frame, rewrite the file truncated (new I/O the backend does not do today).
 
 ## Milestone T open questions
-- **Auto as the shipped-action default?** Whether `CAPTURE_ITEM`/`CAPTURE_TRACK`/
-  `CAPTURE_MASTER` (currently all TailMode::None) flip to Auto, gain a "…with tail"
-  variant, or take a modifier. Product call for Daniel; **leaning** paired variant /
-  toggle over silently changing the exact-bounds default. Not blocking T1 (the
-  request-level three-state contract is independent). (touches `render_settings.cpp`
-  action table + `actions`.)
+- **Auto as the shipped-action default?** Whether `CAPTURE_ITEM`/`CAPTURE_TRACK`
+  (currently all TailMode::None) flip to Auto, gain a "…with tail" variant, or take
+  a modifier. Product call for Daniel; **leaning** paired variant / toggle over
+  silently changing the exact-bounds default. Not blocking T1 (the request-level
+  three-state contract is independent). (touches `render_settings.cpp` action table +
+  `actions`.)
 
 ---
 

docs/product/capture-tail.md

@@ -173,7 +173,7 @@ as configurable — noted below — not to let a single request uncap it.)
 The request already has `renderTail: bool` + `tailMs: double`. The auto-trim mode
 adds a third state, so the wiring is a small enum, not a bool:
 
-- **None** (default for null-test / verify captures, and the current three-scope
+- **None** (default for null-test / verify captures, and the current two-scope
   action defaults): `RENDER_TAILFLAG = 0`, `RENDER_TAILMS = 0`, normalize =
   disable-all. Exact bounds. Byte-identical to today.
 - **Auto** (the new user-facing default for tail-on captures): tailFlag `1`,
@@ -194,8 +194,8 @@ applies the returned values.
 ## The realtime path (parallel, follow-on)
 
 The M8 `RealtimeRecordBackend` (`src/capture_realtime.cpp`) does **not** drive
-`RENDER_*` at all — it records the master send into a hidden temp track over a time
-selection. So none of the offline tail machinery reaches it. It needs a **parallel**
+`RENDER_*` at all — it taps the selected track's own output (post-fader, pre-parent)
+into a hidden temp track over a time selection (track scope only). So none of the offline tail machinery reaches it. It needs a **parallel**
 tail path, and it is explicitly a **follow-on to the offline tail** (offline lands
 first; realtime tail is a later increment).
 
@@ -260,7 +260,7 @@ held to bit-identical repeats.
   dry no-tail capture re-inserted at its source position must null against the
   source; a tail would extend the file past the source region and break the null.
   **The tail must be OFF for null-test and verification captures** — this is a hard
-  rule, not a default. (The three-scope capture *actions* may default to a tail once
+  rule, not a default. (The two capture *actions* may default to a tail once
   this ships; the *verify* action never does.)
 - **Determinism holds for offline.** The offline auto-trim path is deterministic:
   fixed threshold + fixed cap + a boundary-only trim = two identical requests
@@ -270,8 +270,6 @@ held to bit-identical repeats.
   The tail render still goes through `FxBypassGuard` for track/item scopes
   (`render_settings.h §FxBypassPlan`, `CLAUDE.md §Capture FX scope`). This is
   exactly what we want: the tail is the *in-scope FX decay*.
-  - **Master scope:** whole chain in scope → the tail is the full master-chain
-    reverb/release decay. Correct.
   - **Track scope:** the track's own FX are in scope, ancestors/master bypassed →
     the tail is **the track's own reverb/delay decay**, not the parent bus's. A track
     with a reverb plugin captures that reverb's tail; a track feeding a folder reverb
@@ -386,8 +384,8 @@ Neither is in scope now; both are single-constant seams so promotion is cheap.
   trailing edge, and the tail is appended after `ENDPOS`. But a range that itself
   ends in near-silence before a loud transient is the edge case to check the trim
   doesn't over-eat.)
-- **Auto as the action default?** Should the three shipped capture actions
-  (`CAPTURE_ITEM` / `CAPTURE_TRACK` / `CAPTURE_MASTER`, currently all TailMode::None
+- **Auto as the action default?** Should the two shipped capture actions
+  (`CAPTURE_ITEM` / `CAPTURE_TRACK`, currently all TailMode::None
   per `render_settings.cpp §captureActionTable`) flip to Auto tail by default once
   this ships, or should tail be a separate action variant / a modifier? Product call
   for Daniel. **Leaning:** a per-action-family toggle or a paired "…​with tail"