fix(studio): address family B timeline review findings

- revert diamond selection when a rejected retime leaves the source in place
- clear project-local ease focus and expansion on player store reset
- share one static-position-hold predicate across the tween cache
- invalidate the GSAP cache even when a group timing rewrite throws
- stamp each lane keyframe's ease from its own source tween
- memoize property lanes and row offsets so memo'd diamond lanes hold
- use the editable tween duration for drag position commits
- restore the pre-t=0 pad in the all-collapsed content origin
- clamp the drag ghost and drop placeholder to the collapsed clip height
- aria-expanded on the layer disclosure, aria-pressed plus state-specific
  labels on the keyframe toggle, 24px chevron targets, focus-visible parity

packages/studio/src/hooks/useTimelineGroupEditing.ts

@@ -312,25 +312,32 @@ export function useTimelineGroupEditing({
         // reload (see the trackOnly doc above). Mixed batches (any start
         // change) keep the full fallback below.
         if (trackOnly) return;
-        await finishGroupTimingGsapFallback({
-          projectId,
-          iframe: previewIframeRef.current,
-          reloadPreview,
-          label: "Move timeline clips",
-          errorLabel: "Failed to shift GSAP positions",
-          coalesceKey,
-          recordEdit,
-          activeCompPath,
-          changes,
-          resolveChangePath: (element) => targetPathFor(element, activeCompPath),
-          mutateChange: (change, changePath) => {
-            const delta = change.start - change.element.start;
-            const domId = change.element.domId;
-            if (delta === 0 || !domId) return null;
-            return shiftGsapPositions(projectId, changePath, domId, delta);
-          },
-        });
-        invalidateGsapCache?.();
+        // The timing persist above already committed to disk, so the cached
+        // GSAP read is stale whether or not the position rewrite succeeded —
+        // invalidate on the error path too (matches the single-element path's
+        // `.finally`), or a failed rewrite leaves the editor reading old tweens.
+        try {
+          await finishGroupTimingGsapFallback({
+            projectId,
+            iframe: previewIframeRef.current,
+            reloadPreview,
+            label: "Move timeline clips",
+            errorLabel: "Failed to shift GSAP positions",
+            coalesceKey,
+            recordEdit,
+            activeCompPath,
+            changes,
+            resolveChangePath: (element) => targetPathFor(element, activeCompPath),
+            mutateChange: (change, changePath) => {
+              const delta = change.start - change.element.start;
+              const domId = change.element.domId;
+              if (delta === 0 || !domId) return null;
+              return shiftGsapPositions(projectId, changePath, domId, delta);
+            },
+          });
+        } finally {
+          invalidateGsapCache?.();
+        }
       }).catch((error) => {
         // Failed persist: revert the optimistic duration readout + live root
         // alongside the gesture owner's store rollback.
@@ -410,34 +417,40 @@ export function useTimelineGroupEditing({
             coalesceMs,
           );
         }
-        await finishGroupTimingGsapFallback({
-          projectId,
-          iframe: previewIframeRef.current,
-          reloadPreview,
-          label: "Resize timeline clips",
-          errorLabel: "Failed to scale GSAP positions",
-          coalesceKey,
-          recordEdit,
-          activeCompPath,
-          changes,
-          resolveChangePath: (element) => targetPathFor(element, activeCompPath),
-          mutateChange: (change, changePath) => {
-            const domId = change.element.domId;
-            const timingChanged =
-              change.start !== change.element.start || change.duration !== change.element.duration;
-            if (!timingChanged || !domId) return null;
-            return scaleGsapPositions(
-              projectId,
-              changePath,
-              domId,
-              change.element.start,
-              change.element.duration,
-              change.start,
-              change.duration,
-            );
-          },
-        });
-        invalidateGsapCache?.();
+        // See the move path: the timing persist is already on disk, so the GSAP
+        // cache must be invalidated even when the position rewrite throws.
+        try {
+          await finishGroupTimingGsapFallback({
+            projectId,
+            iframe: previewIframeRef.current,
+            reloadPreview,
+            label: "Resize timeline clips",
+            errorLabel: "Failed to scale GSAP positions",
+            coalesceKey,
+            recordEdit,
+            activeCompPath,
+            changes,
+            resolveChangePath: (element) => targetPathFor(element, activeCompPath),
+            mutateChange: (change, changePath) => {
+              const domId = change.element.domId;
+              const timingChanged =
+                change.start !== change.element.start ||
+                change.duration !== change.element.duration;
+              if (!timingChanged || !domId) return null;
+              return scaleGsapPositions(
+                projectId,
+                changePath,
+                domId,
+                change.element.start,
+                change.element.duration,
+                change.start,
+                change.duration,
+              );
+            },
+          });
+        } finally {
+          invalidateGsapCache?.();
+        }
       }).catch((error) => {
         // Failed persist: revert the optimistic duration readout + live root
         // alongside the gesture owner's store rollback.