fix(studio): close the review findings that survived the stack

Selector reads now go through one inverse of `idSelector`. Every writer emits
`[id="01-hook-hero"]` for an id a `#id` selector can't address, but the readers
still matched `#id` only, so the post-commit keyframe-cache refresh, the AST
load and the remove-all-keyframes clear all silently skipped exactly the ids
`idSelector` was added to support.

A keyframe merged from two tweens with different eases kept whichever ease
iterated last. Readers that don't check `easeAmbiguous` showed a curve from a
different animation than an edit would target, so the ambiguous flag now clears
`ease` instead of leaving an arbitrary one behind.

One tolerance for "the playhead is on this keyframe". The motion-path drag used
0.05% while the toolbar and the playhead apply used 1%, so a drag that landed a
fraction of a percent off an authored waypoint skipped the update-point branch
and appended a near-duplicate. `buildTemporalArcKeyframes` now owns the
invariant and replaces any keyframe inside the tolerance, rather than trusting
each caller's own pre-check.

The pending-retime bookkeeping matches on keyframe identity, not just on
"something is near that percentage" — an evenly spaced row cleared the entry off
an unrelated sibling. The neighbour clamp composes pending destinations in
before sorting, so a second drag can't cross a neighbour that already moved.

Also: `keyframeCache`/`gsapAnimations` setters return the same state for a write
that changes nothing (every no-op re-rendered every subscriber), the auto-expand
set drops clips that left the source so an undo/paste under the same id expands
again, `invalidateGsapCache` has a stable identity instead of re-creating the
whole timeline edit context each render, the studio test hook deletes its window
key rather than leaving it enumerable as undefined, and the past-last-row
extrapolation documents why it uses TRACK_H where the pre-first-row branch uses
row 0's own height.

Covers `idFromSelector` round-trips, the insert boundary band across plain,
expanded and unusable row heights, and the collapsed selection key for a
colon-bearing element id.

packages/studio/src/hooks/keyframeCacheAstLoad.ts

@@ -11,18 +11,13 @@ import {
   elementCacheKeys,
   writeGsapAnimationsForElement,
 } from "./gsapKeyframeCacheHelpers";
-import { toClipKeyframes } from "./gsapShared";
+import { idFromSelector, toClipKeyframes } from "./gsapShared";
 import {
   deduplicateKeyframes,
   isStaticPositionHold,
   synthesizeFlatTweenKeyframes,
 } from "./gsapTweenSynth";
 
-function extractIdFromSelector(selector: string): string | null {
-  const match = selector.match(/^#([\w-]+)/);
-  return match ? match[1] : null;
-}
-
 /**
  * Resolve a tween's target selector to the ids of the element(s) it animates.
  * A bare `#id` resolves directly; anything else (a class like `.dot`, a group
@@ -36,10 +31,13 @@ export function resolveSelectorElementIds(
   selector: string,
   doc: Document | null | undefined,
 ): string[] {
-  const bareId = selector.match(/^#([\w-]+)$/);
-  if (bareId) return [bareId[1]];
+  // A whole-selector id match (either shape) addresses exactly one element.
+  const bareId = /^(#[\w-]+|\[id="(?:\\.|[^"\\])*"\])$/.test(selector)
+    ? idFromSelector(selector)
+    : null;
+  if (bareId) return [bareId];
   if (!doc) {
-    const lead = extractIdFromSelector(selector);
+    const lead = idFromSelector(selector);
     return lead ? [lead] : [];
   }
   const ids = new Set<string>();
@@ -51,7 +49,7 @@ export function resolveSelectorElementIds(
         if (el.id) ids.add(el.id);
       }
     } catch {
-      const lead = extractIdFromSelector(sel);
+      const lead = idFromSelector(sel);
       if (lead) ids.add(lead);
     }
   }