fix: add progress logging during silent render pipeline stages (#1220)

* fix: add progress logging during silent render pipeline stages

The render pipeline only updates progress at stage boundaries (5%, 10%,
25%), leaving multi-minute gaps with zero log output on low-memory
hardware. This adds log.info calls at key sub-steps within the three
silent stages:

- Probe stage (5%): browser launch, session initialization, duration
  discovery, media asset discovery, audio volume automation, video
  visibility window detection
- Video extraction (10%): per-video extraction progress
- Calibration (25%): browser launch, session initialization,
  per-frame calibration progress, final cost estimate

Also adds 30-second heartbeat timers for the two initializeSession
calls (probe and calibration) that can individually take minutes on
constrained hardware.

Closes #1218

* fix: resolve CI failures in typecheck, runtime seek test, and timeline test

- Make handleGsapMaterializeKeyframes optional in DomEditSessionSlice
  and use optional chaining at the call site (not yet wired)
- Update GSAP adapter seek test to expect nudge+seek pattern
  (totalTime with suppressEvents:true followed by actual seek)
- Fix Timeline canvas height test to use TRACK_H constant (48)
  instead of stale hardcoded value (72)

* refactor: extract helpers to meet 600-line file size limit

- App.tsx (603→594): extract StudioToast component
- useDomEditSession.ts (688→600): extract useGsapSelectionHandlers hook
- Timeline.tsx (614→557): extract useTimelineAssetDrop hook
- PropertyPanel.tsx (647→584): extract TimingSection to propertyPanelTimingSection

* style: fix formatting in TimelineToolbar

packages/studio/src/components/TimelineToolbar.tsx

@@ -125,8 +125,8 @@ function useKeyframeToggle(session?: DomEditSessionSlice) {
     ? async () => {
         const t = usePlayerStore.getState().currentTime;
         if (kfAnim?.keyframes) {
-          if (kfAnim.hasUnresolvedKeyframes && session.handleGsapMaterializeKeyframes) {
-            await session.handleGsapMaterializeKeyframes(kfAnim.id);
+          if (kfAnim.hasUnresolvedKeyframes) {
+            await session.handleGsapMaterializeKeyframes?.(kfAnim.id);
           }
           const elStart = Number.parseFloat(sel.dataAttributes?.start ?? "0") || 0;
           const elDuration = Number.parseFloat(sel.dataAttributes?.duration ?? "1") || 1;