fix(sdk): fail loudly on Phase 3b ops; add sdk to root build pipeline

- applyOp throws UnsupportedOpError (code E_UNSUPPORTED_OP) for the 9
  parser-backed ops instead of silently no-opping — callers must never
  believe an animation edit succeeded when nothing was mutated
- validateOp returns false for Phase 3b ops so can() feature-detects
- root package.json build filter now includes @hyperframes/sdk (package is
  dist-only; top-level build previously produced no SDK artifacts).
  publish.yml intentionally NOT updated — sdk stays unpublished until
  Phase 3 completes.

Adversarial-review findings F3 + F4.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Author: vanceingalls

package.json

@@ -11,7 +11,7 @@
   "type": "module",
   "scripts": {
     "dev": "bun run studio",
-    "build": "bun run --filter @hyperframes/core build && bun run --filter '@hyperframes/{core,engine,producer,player,studio,shader-transitions,aws-lambda,gcp-cloud-run}' build && bun run --filter @hyperframes/cli build",
+    "build": "bun run --filter @hyperframes/core build && bun run --filter '@hyperframes/{core,engine,producer,player,studio,shader-transitions,aws-lambda,gcp-cloud-run,sdk}' build && bun run --filter @hyperframes/cli build",
     "build:producer": "bun run --filter @hyperframes/producer build",
     "studio": "bun run --filter @hyperframes/studio dev",
     "build:hyperframes-runtime": "bun run --filter @hyperframes/core build:hyperframes-runtime",

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

@@ -361,3 +361,30 @@ describe("validateOp", () => {
     expect(validateOp(fresh(), { type: "setCompositionMetadata", width: 100 })).toBe(true);
   });
 });
+
+// ─── Phase 3b ops — fail loudly, feature-detectable ───────────────────────────
+
+describe("Phase 3b ops", () => {
+  it("applyOp throws UnsupportedOpError instead of silently no-opping", () => {
+    expect(() =>
+      applyOp(fresh(), {
+        type: "addGsapTween",
+        target: "hf-title",
+        id: "tw-1",
+        tween: { method: "from", fromProperties: { opacity: 0 } },
+      }),
+    ).toThrowError(/Phase 3b/);
+  });
+
+  it("validateOp returns false so can() feature-detects", () => {
+    expect(validateOp(fresh(), { type: "removeGsapTween", animationId: "tw-1" })).toBe(false);
+    expect(
+      validateOp(fresh(), {
+        type: "addGsapTween",
+        target: "hf-title",
+        id: "tw-1",
+        tween: { method: "from", fromProperties: { opacity: 0 } },
+      }),
+    ).toBe(false);
+  });
+});

packages/sdk/src/engine/mutate.ts

@@ -40,6 +40,32 @@ export interface MutationResult {
 
 const EMPTY: MutationResult = { forward: [], inverse: [] };
 
+/** Ops that require the Phase 3b parser-backed engine (meriyah/css-tree). */
+const PHASE3B_OPS = new Set([
+  "setClassStyle",
+  "addGsapTween",
+  "setGsapTween",
+  "setGsapKeyframe",
+  "addGsapKeyframe",
+  "removeGsapKeyframe",
+  "removeGsapTween",
+  "addLabel",
+  "removeLabel",
+]);
+
+// Re-exported from the package entry in the next stacked PR (#1325).
+// fallow-ignore-next-line unused-export
+export class UnsupportedOpError extends Error {
+  readonly code = "E_UNSUPPORTED_OP";
+  constructor(opType: string) {
+    super(
+      `Op '${opType}' requires the Phase 3b parser-backed engine and is not available yet. ` +
+        `Use can(op) to feature-detect before dispatching.`,
+    );
+    this.name = "UnsupportedOpError";
+  }
+}
+
 // ─── Target normalization ────────────────────────────────────────────────────
 
 function targets(target: HfId | HfId[]): HfId[] {
@@ -75,7 +101,9 @@ export function applyOp(parsed: ParsedDocument, op: EditOp): MutationResult {
       return handleSetCompositionMetadata(parsed, op);
     case "setVariableValue":
       return handleSetVariableValue(parsed, op.id, op.value);
-    // Phase 3b parser-backed ops — pass through without mutation for now
+    // Phase 3b parser-backed ops — fail loudly rather than silently no-op:
+    // a caller must never believe an animation edit succeeded when nothing
+    // was mutated and no patch was emitted.
     case "setClassStyle":
     case "addGsapTween":
     case "setGsapTween":
@@ -85,7 +113,7 @@ export function applyOp(parsed: ParsedDocument, op: EditOp): MutationResult {
     case "removeGsapTween":
     case "addLabel":
     case "removeLabel":
-      return EMPTY;
+      throw new UnsupportedOpError(op.type);
   }
 }
 
@@ -349,8 +377,9 @@ export function validateOp(parsed: ParsedDocument, op: EditOp): boolean {
       return findRoot(parsed.document) !== null;
     case "setCompositionMetadata":
       return true;
-    // Phase 3b — defer validation; allow through
+    // Phase 3b — not implemented yet; can() must report false so callers
+    // can feature-detect instead of hitting UnsupportedOpError.
     default:
-      return true;
+      return !PHASE3B_OPS.has(op.type);
   }
 }