fix(studio): address PR review — restore rollback, fix probe race, harden edit suppression

Restore rollback path: enqueueEdit now returns the queued promise so
Promise.resolve(handler(...)).catch(rollback) in useTimelineClipDrag
fires correctly on save failure. Handlers return the promise chain.

Fix lost-update race in probe enrichment: use zustand's functional
setState so concurrent probe completions each read the latest state
atomically instead of all reading the same stale snapshot.

Harden file-change suppression: pendingTimelineEditPathRef is now a
Set<string> with exact-match lookup instead of single-slot + endsWith.
Multiple concurrent edits on different files are all suppressed correctly.

Remove dead canOffsetTrimClipStart function and its tests — no longer
called after the capability gate simplification.

Document runtime sync mechanism: added comment explaining that the
runtime re-reads data attributes on each sync tick (init.ts:1324-1368).

Fix comment wording in patchIframeDomTiming catch block.

packages/studio/src/hooks/usePreviewPersistence.ts

@@ -30,7 +30,7 @@ interface UsePreviewPersistenceParams {
   domEditSaveTimestampRef: React.MutableRefObject<number>;
   /** Tracks in-flight timeline edits that patch the iframe DOM directly. File-change
    *  events for these paths are always suppressed since the preview is already up-to-date. */
-  pendingTimelineEditPathRef?: React.MutableRefObject<string | null>;
+  pendingTimelineEditPathRef?: React.MutableRefObject<Set<string>>;
   /** Called to reload the preview after undo/redo or external file changes. */
   reloadPreview: () => void;
 }
@@ -167,9 +167,8 @@ export function usePreviewPersistence({
       const changedPath = readStudioFileChangePath(payload);
       if (!changedPath) return;
       const recentDomEditSave = Date.now() - domEditSaveTimestampRef.current < 4000;
-      const pendingPath = pendingTimelineEditPathRef?.current;
-      if (pendingPath && changedPath.endsWith(pendingPath)) {
-        pendingTimelineEditPathRef!.current = null;
+      if (pendingTimelineEditPathRef?.current.has(changedPath)) {
+        pendingTimelineEditPathRef.current.delete(changedPath);
         return;
       }
       if (!recentDomEditSave) {