Ψ-W3 remediation: fix the verify doc's wrong render source, add missing content checks, soften unverified claims

Corrected the Render-dialog source name the refusal's evidence depends on, added a by-ear content check and a file-size channel proxy, and stopped two comments from overclaiming.

src/core/capture/render_settings.cpp

@@ -117,6 +117,11 @@ bool isMultiTrackStemRender(SourceMode mode, int sourceTrackCount) {
 }
 
 std::string multiTrackRefusalMessage(CaptureScope scope) {
+    // Deliberately does not name realtime capture as a way out, though it is the one
+    // action that sums correctly here: realtime is non-deterministic (hardware/performed
+    // FX, no bit-identical-repeats guarantee), so pointing an offline refusal at it would
+    // trade one invariant for another rather than just naming a substitute. A stated
+    // choice, not an oversight.
     switch (scope) {
         case CaptureScope::Item:
             return "This range is narrower than the selected items, so it renders "

src/core/capture/render_settings.h

@@ -1,8 +1,9 @@
 #pragma once
 // render_settings — the REAPER-free logic behind the capture action family:
 // sourceMode -> RENDER_SETTINGS bits, P_RAZOREDITS parsing + range union,
-// razor-else-time inference, the FX-scope bypass plan, and the capture-action
-// table main.cpp iterates. Bit MEANINGS below are transcribed verbatim from
+// razor-else-time inference, the FX-scope bypass plan, the capture-action
+// table main.cpp iterates, and the multi-track-stem refusal + its user-facing
+// message text. Bit MEANINGS below are transcribed verbatim from
 // reaper_plugin_functions.h; the CHOICE of which bits each mode sets is tested.
 
 #include <string>

src/core/capture/wav_codec.h

@@ -129,7 +129,11 @@ enum class MonoCollapseOutcome {
 
 // The capture message's collapse suffix — empty for Declined, so a capture that had
 // nothing to collapse reads exactly as it did before the collapse existed. Shared by
-// both backends so one outcome cannot be reported two ways.
+// both backends so one outcome cannot be reported two ways. NOT user-observable on its
+// own: CaptureResult::message on a successful capture is never printed by any caller, so
+// the Collapsed/Failed text this returns reaches no one today — the one observable
+// channel for a genuine Failed outcome is the backends' own reportCollapseFailure
+// console line.
 std::string monoCollapseSuffix(MonoCollapseOutcome outcome);
 
 // --- Content identity (dedup hashes) -----------------------------------------