fix(studio): scope the per-file keyframe-cache clear to its own keys

R3 review follow-ups on the keyframe cache:

- clearKeyframeCacheForFile collected ids from the index.html alias prefix
  too, so a re-scan of one composition file wiped rows a sibling file had
  just written (several files re-scan concurrently). Only the file's own
  prefixed keys name the ids now; clearKeyframeCacheForElement still takes
  the alias and bare key with them.
- toClipKeyframes fell back to a fixed 1s tween duration, which put a
  duration-less tween's keyframes at a percentage no edit path agreed with.
  It now spans the clip, matching resolveEditableTweenDuration.
- collectAnimatableKeyframeProperties takes `object` so call sites drop
  their `as Record<string, unknown>` casts.

Regression tests cover both fixes.

packages/studio/src/hooks/gsapKeyframeCacheHelpers.test.ts

@@ -84,6 +84,20 @@ describe("clearKeyframeCacheForFile", () => {
     }
   });
 
+  // Several composition files re-scan concurrently, so a clear that walked the
+  // index.html alias would delete rows a sibling file had just written.
+  it("leaves an index.html-owned element alone when another file re-scans", () => {
+    seed("index.html#title");
+    seed("title");
+    seed("comp.html#a");
+
+    clearKeyframeCacheForFile("comp.html");
+
+    expect(cache().has("index.html#title")).toBe(true);
+    expect(cache().has("title")).toBe(true);
+    expect(cache().has("comp.html#a")).toBe(false);
+  });
+
   it("leaves entries that belong to a different source file", () => {
     seed("comp.html#a");
     seed("a");

packages/studio/src/hooks/gsapKeyframeCacheHelpers.ts

@@ -92,22 +92,22 @@ export function clearKeyframeCacheForElement(sourceFile: string, elementId: stri
 
 /**
  * Clear every cached element of `sourceFile` before a full re-scan repopulates
- * it. Collects the element ids that currently have a prefixed or index.html
- * fallback key for the file and drops each through clearKeyframeCacheForElement
- * so the bare key goes too — an element whose keyframes were removed (and so is
- * absent from the re-scan) leaves no stale bare entry behind.
+ * it. Only the file's OWN prefixed keys name the ids to clear: every write sets
+ * the prefixed key (see elementCacheKeys), so the file's elements are all
+ * reachable that way, and clearKeyframeCacheForElement then takes the
+ * index.html alias and the bare key with them — an element whose keyframes were
+ * removed (and so is absent from the re-scan) leaves no stale bare entry
+ * behind. Reading the alias prefix here instead would collect ids owned by
+ * OTHER files, and several files re-scan concurrently, so this file's clear
+ * would wipe the entries a sibling file had just written.
  */
 export function clearKeyframeCacheForFile(sourceFile: string): void {
   const { keyframeCache, gsapAnimations } = usePlayerStore.getState();
   const sfPrefix = `${sourceFile}#`;
-  const fallbackPrefix = "index.html#";
   const ids = new Set<string>();
   for (const key of [...keyframeCache.keys(), ...gsapAnimations.keys()]) {
-    const matchesFile =
-      key.startsWith(sfPrefix) || (sourceFile !== "index.html" && key.startsWith(fallbackPrefix));
-    if (!matchesFile) continue;
-    const hashIdx = key.indexOf("#");
-    if (hashIdx !== -1) ids.add(key.slice(hashIdx + 1));
+    if (!key.startsWith(sfPrefix)) continue;
+    ids.add(key.slice(sfPrefix.length));
   }
   for (const id of ids) {
     clearKeyframeCacheForElement(sourceFile, id);

packages/studio/src/hooks/gsapShared.test.ts

@@ -4,6 +4,7 @@ import {
   idSelector,
   isInstantHold,
   parsePercentageKeyframes,
+  toClipKeyframes,
   toClipPercentage,
 } from "./gsapShared";
 
@@ -122,3 +123,26 @@ describe("toClipPercentage", () => {
     expect(toClipPercentage(5, 0, 0, 42)).toBe(42);
   });
 });
+
+describe("toClipKeyframes", () => {
+  const durationless: GsapAnimation = {
+    id: "a1",
+    method: "to",
+    targetSelector: "#box",
+    vars: {},
+    resolvedStart: 0,
+  } as GsapAnimation;
+
+  // A tween with no duration spans its clip everywhere else in Studio
+  // (resolveEditableTweenDuration), so the cache rows have to agree: a fixed 1s
+  // basis put the end keyframe at 25% of a 4s clip instead of 100%.
+  it("spans the clip when the tween has no duration", () => {
+    const rows = toClipKeyframes([{ percentage: 0 }, { percentage: 100 }], durationless, 0, 4);
+    expect(rows.map((row) => row.percentage)).toEqual([0, 100]);
+  });
+
+  it("keeps the tween percentage and the animation identity on every row", () => {
+    const rows = toClipKeyframes([{ percentage: 50 }], durationless, 0, 4);
+    expect(rows[0]).toMatchObject({ tweenPercentage: 50, animationId: "a1" });
+  });
+});

packages/studio/src/hooks/gsapShared.ts

@@ -145,9 +145,7 @@ export interface ParsedPercentageKeyframes {
   easeEach?: string;
 }
 
-function collectAnimatableKeyframeProperties(
-  entry: Record<string, unknown>,
-): Record<string, number | string> {
+function collectAnimatableKeyframeProperties(entry: object): Record<string, number | string> {
   const properties: Record<string, number | string> = {};
   for (const [property, value] of Object.entries(entry)) {
     if (property === "ease") continue;
@@ -185,7 +183,7 @@ export function parsePercentageKeyframes(
     steps.forEach((entry, i) => {
       if (!entry || typeof entry !== "object") return;
       const percentage = steps.length > 1 ? Math.round((i / (steps.length - 1)) * 1000) / 10 : 0;
-      const properties = collectAnimatableKeyframeProperties(entry as Record<string, unknown>);
+      const properties = collectAnimatableKeyframeProperties(entry);
       if (Object.keys(properties).length > 0) keyframes.push({ percentage, properties });
     });
     return keyframes.length > 0 ? { keyframes } : null;
@@ -199,7 +197,7 @@ export function parsePercentageKeyframes(
     const pctMatch = key.match(/^(\d+(?:\.\d+)?)%$/);
     if (!pctMatch || !val || typeof val !== "object") continue;
     const percentage = parseFloat(pctMatch[1]);
-    const properties = collectAnimatableKeyframeProperties(val as Record<string, unknown>);
+    const properties = collectAnimatableKeyframeProperties(val);
     if (Object.keys(properties).length > 0) {
       keyframes.push({ percentage, properties });
     }
@@ -253,7 +251,10 @@ export function toClipKeyframes<T extends { percentage: number }>(
   }
 > {
   const tweenStart = anim.resolvedStart ?? (typeof anim.position === "number" ? anim.position : 0);
-  const tweenDuration = anim.duration ?? 1;
+  // A duration-less tween spans the clip, the same rule the edit paths use
+  // (resolveEditableTweenDuration). A fixed 1s here put its keyframes at a
+  // percentage no editor agreed with.
+  const tweenDuration = anim.duration ?? clipDuration;
   return source.map((keyframe) => ({
     ...keyframe,
     percentage: toClipPercentage(