Gate the FX reclaimer on the transport, both directions; move the release's persist off the drain and onto the project save

The drain no longer dirties a project on its own initiative — a spent park record rides the user's next save via OnSaveExtensionConfig.

src/shell/persist/ext_state_io.cpp

@@ -211,6 +211,16 @@ bool ReaSamplerSession::saveViewStateOnly() {
     return true;
 }
 
+// Its twin bar the dirty mark — the one line that differs is the whole point of the
+// split, so the two stay spelled out rather than folded behind a flag.
+bool ReaSamplerSession::flushViewState() {
+    ReaProject* proj = activeSavedProject();
+    if (!proj) return false;
+
+    writeViewState(proj, view_);
+    return true;
+}
+
 bool ReaSamplerSession::writeAssignmentRequest(const std::string& wire) {
     ReaProject* proj = activeSavedProject();
     if (!proj) return false;

src/shell/persist/session.h

@@ -144,6 +144,13 @@ public:
     // Returns on the SAME rule as saveToActiveProject above, prohibition included.
     bool saveViewStateOnly();
 
+    // The same write with the dirty mark OMITTED, for a caller already inside REAPER's
+    // own project save: marking dirty there would leave the project modified the instant
+    // it was saved, which is the whole reason that caller exists (fx_reclaim's
+    // ReleaseFlush). Not a general-purpose sibling — a mutation site that skips the dirty
+    // mark silently loses its write when the user closes without saving.
+    bool flushViewState();
+
     // Report-only prune dry-run: feeds the pure core with (present, referenced,
     // owned) — `present` from the folder enumeration, the other two from the
     // tracking authority. FAIL-SAFE: tracking state the authority cannot read