refactor(capture): drop master scope; realtime taps selected track

Capture is now item + track only (master removed as a scope; still bypassed
as out-of-scope chain). Realtime records the selected track's own output via
per-track post-fader sends into a hidden temp track, fixing the silent file.

src/render_settings.h

@@ -66,18 +66,20 @@ RenderSettingsChoice renderSettingsFor(SourceMode mode, double wetDry);
 
 // --- Capture scope: the FX-scope invariant (Daniel, critical) ----------------
 //
-// Three FX scopes. The render RANGE (razor-else-time) is orthogonal to the scope.
+// Two FX scopes. The render RANGE (razor-else-time) is orthogonal to the scope.
 //   Item   -> item/take FX ONLY (no track, no parent/folder, no master FX).
 //   Track  -> item FX + the selected track's OWN track FX (no parent/folder/master).
-//   Master -> the whole chain (nothing bypassed).
+// There is NO master scope: to capture the master you render a track instead. The
+// master track's FX/gain/pan are still NEUTRALIZED as part of the out-of-scope
+// chain for both item and track captures (bypassMaster below) — master is a
+// bypass target, not a capture scope.
 enum class CaptureScope {
     Item,
     Track,
-    Master,
 };
 
 // The render source mode each scope drives. Item captures selected items, Track
-// captures selected tracks (via master), Master captures the master mix.
+// captures selected tracks (via master).
 SourceMode sourceModeForScope(CaptureScope scope);
 
 // --- Range inference: razor-else-time (orthogonal to scope) -------------------
@@ -142,7 +144,7 @@ RazorRange razorUnionBounds(const std::vector<RazorRange>& ranges);
 
 // --- Capture-action taxonomy (the bindable set main.cpp registers) -----------
 //
-// One row per bindable SCOPE action. Three scopes (item / track / master); the
+// One row per bindable SCOPE action. Two scopes (item / track); the
 // range each captures (razor-else-time) is inferred at fire time, not a mode.
 // Tail is OFF for every row (exact bounds); a tail-on variant is a later opt-in,
 // YAGNI now. Bounded, discoverable, NO dialogs (the tool's no-clutter ethos).
@@ -153,17 +155,16 @@ struct CaptureActionDef {
     const char*  commandString;  // CEREBELLUM_REASAMPLER_… FOREVER-STABLE id string
     const char*  description;    // Actions-list label
     const char*  baseName;       // file-stem base for this capture
-    CaptureScope scope;          // FX scope (item / track / master)
+    CaptureScope scope;          // FX scope (item / track)
 };
 
 // The capture-action table. Iterated by main.cpp to register the family and route
 // each fired command back to its definition. Kept here (pure) so the taxonomy is
 // one testable list, not scattered registration code.
 //
-// Three scope rows: CAPTURE_ITEM, CAPTURE_TRACK, CAPTURE_MASTER. This replaces the
-// M7 four-mode table (master / tracks / items / razor) — razor is now an inferred
-// range, not a mode, and each scope enforces its FX-scope invariant via
-// fxBypassPlanFor.
+// Two scope rows: CAPTURE_ITEM, CAPTURE_TRACK. There is no master capture — to
+// capture the master you render a track. Razor is an inferred range, not a mode,
+// and each scope enforces its FX-scope invariant via fxBypassPlanFor.
 const std::vector<CaptureActionDef>& captureActionTable();
 
 } // namespace reasampler