fix(core): set __renderReady unconditionally after binding attempt

The capturedTimeline guard broke CSS/WAAPI/Lottie compositions that
have no GSAP timeline — __renderReady was never set, causing the
parity harness to timeout after 30s.

renderSeek works with or without a GSAP timeline (adapter-only
seeking), so the correct invariant is "timeline binding was
attempted" not "a timeline was found." Set __renderReady
unconditionally in all three paths, after bindRootTimelineIfAvailable
has run.

Author: miguel-heygen

packages/core/src/runtime/init.test.ts

@@ -557,7 +557,7 @@ describe("initSandboxRuntimeModular", () => {
     expect(window.__player).toBeDefined();
   });
 
-  it("does not set __renderReady when no timeline is available", () => {
+  it("sets __renderReady even without a GSAP timeline (CSS/WAAPI compositions)", () => {
     const root = document.createElement("div");
     root.setAttribute("data-composition-id", "main");
     root.setAttribute("data-root", "true");
@@ -571,6 +571,6 @@ describe("initSandboxRuntimeModular", () => {
     initSandboxRuntimeModular();
 
     expect(window.__playerReady).toBe(true);
-    expect(window.__renderReady).toBeUndefined();
+    expect(window.__renderReady).toBe(true);
   });
 });

packages/core/src/runtime/init.ts

@@ -1460,9 +1460,7 @@ export function initSandboxRuntimeModular(): void {
       .finally(() => {
         externalCompositionsReady = true;
         bindRootTimelineIfAvailable();
-        if (state.capturedTimeline) {
-          window.__renderReady = true;
-        }
+        window.__renderReady = true;
         runAdapters("discover", state.currentTime);
         bindMediaMetadataListeners();
         installAssetFailureDiagnostics();
@@ -1633,11 +1631,11 @@ export function initSandboxRuntimeModular(): void {
     player._timeline = state.capturedTimeline;
   }
 
-  // __renderReady = timeline is bound, safe for deterministic seeking.
+  // __renderReady = timeline binding attempted, safe for deterministic seeking.
+  // Set unconditionally: renderSeek works with or without a GSAP timeline
+  // (CSS/WAAPI/Lottie compositions use adapter-only seeking).
   // fileServer.ts sets this immediately (no timeline to bind in its runtime).
-  if (state.capturedTimeline) {
-    window.__renderReady = true;
-  }
+  window.__renderReady = true;
 
   // When the bundler inlines compositions, data-composition-src is removed so
   // loadExternalCompositions() is skipped. But inline scripts registering child
@@ -1650,9 +1648,7 @@ export function initSandboxRuntimeModular(): void {
         player._timeline = state.capturedTimeline;
       }
       runAdapters("discover", state.currentTime);
-      if (state.capturedTimeline) {
-        window.__renderReady = true;
-      }
+      window.__renderReady = true;
       postTimeline();
       postState(true);
     }, 0);