fix(sdk): retire duplicate removeGsapKeyframe keyframeIndex variant (review #1498)

EditOp had two removeGsapKeyframe members with the same discriminant but
different shapes (keyframeIndex vs percentage) — TS can't discriminate them and
a handler could get the wrong shape. Per both reviewers (option 2): retire the
keyframeIndex variant. It had no production caller (Studio dispatches percentage
only); removed the dead by-index handleRemoveGsapKeyframe + simplified the
dispatcher. resolveKeyframe stays (setGsapKeyframe still uses keyframeIndex).
Converted the one by-index test to the percentage API.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: vanceingalls

packages/sdk/src/engine/mutate.gsap.test.ts

@@ -400,13 +400,13 @@ describe("setGsapKeyframe", () => {
 });
 
 describe("removeGsapKeyframe", () => {
-  it("removes keyframe at index 1 (50%)", () => {
+  it("removes keyframe at 50%", () => {
     const parsed = fresh(KF_SCRIPT);
     const animId = `[data-hf-id="hf-box"]-to-0-visual`;
     const result = applyOp(parsed, {
       type: "removeGsapKeyframe",
       animationId: animId,
-      keyframeIndex: 1,
+      percentage: 50,
     });
     expect(result.forward).toHaveLength(1);
     const newScript = String(result.forward[0]?.value ?? "");

packages/sdk/src/engine/mutate.ts

@@ -150,9 +150,7 @@ function dispatchRemoveGsapKeyframe(
   parsed: ParsedDocument,
   op: Extract<EditOp, { type: "removeGsapKeyframe" }>,
 ): MutationResult {
-  return "percentage" in op
-    ? handleRemoveGsapKeyframeByPercentage(parsed, op.animationId, op.percentage)
-    : handleRemoveGsapKeyframe(parsed, op.animationId, op.keyframeIndex);
+  return handleRemoveGsapKeyframeByPercentage(parsed, op.animationId, op.percentage);
 }
 
 function applyGsapKeyframeOp(parsed: ParsedDocument, op: EditOp): MutationResult | undefined {
@@ -1003,24 +1001,6 @@ function handleRemoveGsapKeyframeByPercentage(
   return gsapScriptChange(script, newScript);
 }
 
-function handleRemoveGsapKeyframe(
-  parsed: ParsedDocument,
-  animationId: string,
-  keyframeIndex: number,
-): MutationResult {
-  const resolved = resolveKeyframe(parsed, animationId, keyframeIndex);
-  if (!resolved) return EMPTY;
-  const { script, kf, kfs } = resolved;
-  const pct = kf.percentage;
-  // removeKeyframeFromScript matches by percentage; bail if two keyframes share
-  // the same percentage to avoid removing the wrong one.
-  if (kfs.filter((k) => k.percentage === pct).length > 1) return EMPTY;
-  const newScript = removeKeyframeFromScript(script, animationId, pct);
-  if (newScript === script) return EMPTY;
-  setGsapScript(parsed.document, newScript);
-  return gsapScriptChange(script, newScript);
-}
-
 function handleAddLabel(parsed: ParsedDocument, name: string, position: number): MutationResult {
   const script = getGsapScript(parsed.document);
   if (!script) return EMPTY;

packages/sdk/src/types.ts

@@ -101,7 +101,6 @@ export type EditOp =
       position: number;
       value: Record<string, unknown>;
     }
-  | { type: "removeGsapKeyframe"; animationId: string; keyframeIndex: number }
   | { type: "removeGsapKeyframe"; animationId: string; percentage: number }
   | { type: "removeGsapProperty"; animationId: string; property: string; from?: boolean }
   | { type: "removeGsapTween"; animationId: string }