Fix undo-label misnomer, tighten drain-nesting/abort-path docs, mark inferred undo behavior as unverified

Renamed the drain's undo point to "Design View FX state" (it restores as often as it parks). Extended the nesting audit to cover a block opening inside the drain's own block. Marked post-fix undo behavior as inference pending DAW checks.

tests/test_view_fx_park.cpp

@@ -408,6 +408,11 @@ static void testAReEntrantParkCancelsOnlyWhatIsStillPending() {
 }
 
 // -- the drain's undo point --------------------------------------------------
+//
+// These pin fxParkUndoClose's own fold only. The real wroteAnyFx verdict —
+// setOfflineIfChanged -> applyPark/applyRestore -> FxParkUndoBlock::noteWrite
+// -- runs against live REAPER calls and cannot be pinned here; docs/VERIFICATION.md
+// items 51 and 53 are the sole cover for that plumbing being wired correctly.
 
 static void testADrainThatWroteFxClosesItsBlockAsOneNamedFxPoint() {
     const FxParkUndoClose close = fxParkUndoClose(true);
@@ -418,7 +423,7 @@ static void testADrainThatWroteFxClosesItsBlockAsOneNamedFxPoint() {
     // track config or items it never touched.
     CHECK(close.mask == 2);
     CHECK(close.label != nullptr && std::string(close.label) ==
-                                        "ReaSampler: Design View FX park");
+                                        "ReaSampler: Design View FX state");
 }
 
 static void testADrainThatWroteNothingClosesItsBlockAsADiscard() {