fix(studio): compare the reveal request across the id-space boundary

The previous commit's store guard was silently never true. A reveal request
carries the BARE dom id — `revealElementId = runtimeAudioId(keyframeClip)`,
because the panel and the runtime speak that — while the store's ids are
`sourceFile#domId`. So `elementKey === id` compared "music-bed" against
"index.html#music-bed" and the request was still cleared by its own selection.

This is the id-space boundary the branch's own handoff names as the trap most
likely to be re-broken, and it fails exactly as documented: no error, the
feature just never matches. Caught only by driving the real UI — the store said
`selected: "index.html#music-bed"` and `revealSurvived: null` in the same read.

`revealTargetsSelection` now splits the key with the existing
`splitTimelineElementKey` and is a named function in `playerStoreSelection.ts`
so the crossing is stated once, where it happens.

**Verified in the browser, both halves, which had never been watched working:**
- clip NOT selected: clicking a lane label selects the clip, the rack opens, and
  the carve module expands (correct — that lane's node is a carve band). The
  request is consumed and retired to null by the new unmount clear.
- clip ALREADY selected: collapsing the module and clicking the same lane again
  reopens it, which the old value-equality consumption could not do.

studio player: 103 files, 1355 tests. fallow clean.

packages/studio/src/player/store/playerStore.ts

@@ -1,6 +1,6 @@
 import { create } from "zustand";
 import { attachPlayerStoreDevHandle } from "./playerStoreDevHandle";
-import { nextSelectionSet } from "./playerStoreSelection";
+import { nextSelectionSet, revealTargetsSelection } from "./playerStoreSelection";
 import type { MusicBeatAnalysis } from "@hyperframes/core/beats";
 import type { GsapAnimation } from "@hyperframes/core/gsap-parser";
 import type { BeatEditState } from "../../utils/beatEditing";
@@ -541,7 +541,13 @@ export const usePlayerStore = create<PlayerState>((set, get) => ({
       // selection lands afterwards and used to clear the very request that
       // caused it — the panel then read null and the section never opened.
       // Any OTHER selection still drops it: a request aimed elsewhere is stale.
-      const revealSurvives = s.revealedAudioFxTarget?.elementKey === id;
+      //
+      // Compared across the ID-SPACE BOUNDARY, which is why this needs saying:
+      // a request carries the BARE dom id (`runtimeAudioId`, because the panel
+      // and the runtime speak that), while this store's ids are
+      // `sourceFile#domId`. A direct `===` was silently never true — the exact
+      // shape of failure the id-space split produces.
+      const revealSurvives = revealTargetsSelection(s.revealedAudioFxTarget, id);
       return id !== s.selectedElementId
         ? {
             selectedElementId: id,

packages/studio/src/player/store/playerStoreSelection.ts

@@ -1,9 +1,12 @@
 /**
- * Selection-set arithmetic for the player store.
+ * Selection-set arithmetic for the player store, and the reveal request's
+ * cross-id-space match.
  *
  * Its own module so `playerStore.ts` stays under the studio's 600-line cap.
  */
 
+import { splitTimelineElementKey } from "../lib/timelineElementHelpers";
+
 /**
  * The id set a selection change leaves behind.
  *
@@ -19,3 +22,20 @@ export function nextSelectionSet(
   if (preserveSet) return id && current.has(id) ? new Set(current) : new Set<string>();
   return id ? new Set([id]) : new Set<string>();
 }
+
+/**
+ * Is a pending reveal request aimed at the element being selected?
+ *
+ * Compared across the ID-SPACE BOUNDARY, which is why it is a named function:
+ * a request carries the BARE dom id (`runtimeAudioId` — the panel and the
+ * runtime speak that), while the store's ids are `sourceFile#domId`. A direct
+ * `===` between the two is silently never true, which is the exact shape of
+ * failure the split produces and how the reveal came to be dead.
+ */
+export function revealTargetsSelection(
+  request: { elementKey: string } | null,
+  id: string | null,
+): boolean {
+  if (!request || id === null) return false;
+  return request.elementKey === splitTimelineElementKey(id).domId;
+}