Remediate Phase P render-in-place review findings

Fix the ProjectMedia refusal path's false bank claims and file relocation, an unreachable-undo idiom, and eight comment/doc accuracy issues.

src/core/capture/capture_name.h

@@ -59,10 +59,20 @@ std::string formatCaptureStamp(const CaptureStamp& stamp);
 
 CaptureName composeCaptureName(const CaptureNameInputs& in);
 
+// The single source of truth for the word itself — kCaptureTrackPrefixBare and
+// kCaptureTrackPrefix below both expand from this one token, so editing it can never
+// desync captureTrackName's "no readable source name" bare-word fallback from the
+// separator-terminated prefix it is derived from.
+#define REASAMPLER_CAPTURE_TRACK_WORD "Capture"
+
+// The bare word behind kCaptureTrackPrefix, needed by captureTrackName's
+// no-readable-source-name fallback.
+inline constexpr const char* kCaptureTrackPrefixBare = REASAMPLER_CAPTURE_TRACK_WORD;
+
 // Prefixed onto a source track's name to name the track a render-in-place created.
 // A display convention, not a persisted key — unlike a lane prefix or an action-id
 // suffix, changing it later strands nothing.
-inline constexpr const char* kCaptureTrackPrefix = "Capture ";
+inline constexpr const char* kCaptureTrackPrefix = REASAMPLER_CAPTURE_TRACK_WORD " ";
 
 // The new track's name for a render of `sourceName`. IDEMPOTENT — a fixed point on
 // its own output, so a second render over a result track yields "Capture MONEY"