fix(core,cli): address review — guard __renderReady, drop pre-quantization, add tests

- Guard __renderReady with `if (state.capturedTimeline)` in all three
  paths (setTimeout(0) and .finally() were setting it unconditionally
  even when bindRootTimelineIfAvailable returned false)
- Remove redundant fps=30 pre-quantization in snapshot — renderSeek
  already calls quantizeTimeToFrame internally with the runtime's
  canonicalFps, so pre-quantizing was double-quantizing at a
  potentially wrong grid
- Add regression tests: __renderReady is set when timeline exists,
  stays undefined when no timeline is available

packages/cli/src/commands/snapshot.ts

@@ -276,17 +276,14 @@ async function captureSnapshots(
       for (let i = 0; i < positions.length; i++) {
         const time = positions[i]!;
 
-        // 30 = runtime's default canonicalFps (not exposed on PlayerAPI)
         await page.evaluate((t: number) => {
           const player = (window as any).__player;
           if (!player) return;
           const safe = Math.max(0, Number(t) || 0);
-          const frame = Math.floor(safe * 30 + 1e-9);
-          const quantized = frame / 30;
           if (typeof player.renderSeek === "function") {
-            player.renderSeek(quantized);
+            player.renderSeek(safe);
           } else if (typeof player.seek === "function") {
-            player.seek(quantized);
+            player.seek(safe);
           }
           if ((window as any).gsap?.ticker?.tick) {
             (window as any).gsap.ticker.tick();

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

@@ -576,4 +576,52 @@ describe("initSandboxRuntimeModular", () => {
     expect(player?.getTime()).toBeCloseTo(1, 1);
     expect(childTimeline.time()).toBeCloseTo(1, 1);
   });
+
+  it("sets __renderReady only after timeline is bound, not at __playerReady time", async () => {
+    const root = document.createElement("div");
+    root.setAttribute("data-composition-id", "main");
+    root.setAttribute("data-root", "true");
+    root.setAttribute("data-start", "0");
+    root.setAttribute("data-width", "1920");
+    root.setAttribute("data-height", "1080");
+    document.body.appendChild(root);
+
+    (window as Window & { __timelines?: Record<string, RuntimeTimelineLike> }).__timelines = {
+      main: createMockTimeline(10),
+    };
+
+    initSandboxRuntimeModular();
+
+    const win = window as Window & {
+      __playerReady?: boolean;
+      __renderReady?: boolean;
+      __player?: { _timeline: RuntimeTimelineLike | null };
+    };
+
+    expect(win.__playerReady).toBe(true);
+    expect(win.__renderReady).toBe(true);
+    expect(win.__player?._timeline).not.toBeNull();
+  });
+
+  it("does not set __renderReady when no timeline is available", () => {
+    const root = document.createElement("div");
+    root.setAttribute("data-composition-id", "main");
+    root.setAttribute("data-root", "true");
+    root.setAttribute("data-start", "0");
+    root.setAttribute("data-width", "1920");
+    root.setAttribute("data-height", "1080");
+    document.body.appendChild(root);
+
+    (window as Window & { __timelines?: Record<string, RuntimeTimelineLike> }).__timelines = {};
+
+    initSandboxRuntimeModular();
+
+    const win = window as Window & {
+      __playerReady?: boolean;
+      __renderReady?: boolean;
+    };
+
+    expect(win.__playerReady).toBe(true);
+    expect(win.__renderReady).toBeUndefined();
+  });
 });

packages/core/src/runtime/init.ts

@@ -1463,7 +1463,9 @@ export function initSandboxRuntimeModular(): void {
       .finally(() => {
         externalCompositionsReady = true;
         bindRootTimelineIfAvailable();
+        if (state.capturedTimeline) {
           (window as Window & { __renderReady?: boolean }).__renderReady = true;
+        }
         runAdapters("discover", state.currentTime);
         bindMediaMetadataListeners();
         installAssetFailureDiagnostics();
@@ -1650,9 +1652,10 @@ export function initSandboxRuntimeModular(): void {
       if (bindRootTimelineIfAvailable() && state.capturedTimeline !== prevTimeline) {
         player._timeline = state.capturedTimeline;
       }
-      // Re-run adapters to discover new elements
       runAdapters("discover", state.currentTime);
+      if (state.capturedTimeline) {
         (window as Window & { __renderReady?: boolean }).__renderReady = true;
+      }
       postTimeline();
       postState(true);
     }, 0);