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.

tests/test_render_settings.cpp

@@ -297,6 +297,22 @@ static void testRefusalMessagesAreSiblingsWithDistinctExits() {
     CHECK(track.find("selected items") == std::string::npos);
 }
 
+// Golden literals: docs/verify-track-scope-multitrack.md §2 quotes the track message as
+// an exact console match. A substring check alone leaves that doc free to drift from
+// whatever ships, so pin both strings byte-for-byte here.
+static void testRefusalMessagesMatchGoldenLiterals() {
+    CHECK(multiTrackRefusalMessage(CaptureScope::Item) ==
+          "This range is narrower than the selected items, so it renders "
+          "through their tracks -- and those items span more than one track, "
+          "which this shape cannot land as a single file. Capture one track's "
+          "items at a time, or make the range match the items' extent.");
+    CHECK(multiTrackRefusalMessage(CaptureScope::Track) ==
+          "A track capture renders the selected tracks through the master, "
+          "and more than one track cannot land as a single file. Capture one "
+          "track at a time, or route them into a folder/bus track and capture "
+          "that (a folder's own output is its children summed).");
+}
+
 // --- inferRangeSource: razor-else-time (orthogonal to scope) -----------------
 
 static void testRangeInference() {
@@ -396,6 +412,7 @@ int main() {
     testRangedItemScopeRendersTimeBounded();
     testMultiTrackStemRenderIsNamedForRefusal();
     testRefusalMessagesAreSiblingsWithDistinctExits();
+    testRefusalMessagesMatchGoldenLiterals();
     testRangeInference();
     testItemScopeBypassesEverythingButTake();
     testTrackScopeKeepsSelfBypassesAncestorsAndMaster();