fix(engine): retry probe on pollHfReady zero-duration timeout (#1824)

Renders were failing outright with "[FrameCapture] Composition has zero
duration. Runtime ready: false, ..." whenever window.__renderReady didn't
flip true within playerReadyTimeout (45s) — most often under host
contention (e.g. several renders running concurrently), never from a
defect in the composition itself. Confirmed by re-running an affected
composition standalone: it succeeded immediately (initMs ~3.5-4.4s vs.
the 45s timeout it hit under concurrent load).

The probe stage already retries once with a fresh browser session for
exactly this class of "succeeds on retry" infra flakiness (frame
detachment, disconnects, navigation timeouts, launch failures), but
isTransientBrowserError didn't recognize this message, so it fell
through to an immediate, unretried failure.

Match "Composition has zero duration ... Runtime ready: false" as
transient. Left the "Runtime ready: true" case (pollHfReady's fast-fail:
no GSAP timeline and no data-duration) unmatched — that's a genuine
authoring bug, not a timing fluke, and should keep failing fast.

packages/producer/src/services/render/stages/probeStage.test.ts

@@ -69,6 +69,7 @@ mock.module("@hyperframes/engine", () => ({
   // live in frameCapture-transientErrors.test.ts — update both if patterns change.
   isTransientBrowserError: (error: unknown) => {
     const msg = error instanceof Error ? error.message : String(error);
+    if (/Composition has zero duration[\s\S]*Runtime ready: false/.test(msg)) return true;
     return /Navigating frame was detached|Target closed|Session closed|browser has disconnected|Page crashed|Execution context was destroyed|Cannot find context with specified id|Failed to launch the browser process|Navigation timeout of \d+ ms exceeded|ECONNREFUSED/i.test(
       msg,
     );
@@ -337,6 +338,49 @@ describe("runProbeStage — transient browser error retry (#1687)", () => {
     expect(closeCaptureSessionCallCount).toBe(2);
   });
 
+  it("retries once on a pollHfReady zero-duration timeout (renderReady: false) and succeeds", async () => {
+    resetRetryMocks();
+    capturedCfgs.length = 0;
+    initializeSessionError = new Error(
+      "[FrameCapture] Composition has zero duration.\n  Runtime ready: false, __player: true, __hf.seek: true, GSAP timeline: true, data-duration: 53.3s",
+    );
+    initializeSessionFailUntilAttempt = 1;
+
+    const { runProbeStage } = await import("./probeStage.js");
+    const input = makeProbeInput({ cfgForceScreenshot: false, stageForceScreenshot: false });
+
+    const result = await runProbeStage(input);
+
+    expect(initializeSessionCallCount).toBe(2);
+    expect(closeCaptureSessionCallCount).toBe(1);
+    expect(result.duration).toBe(5);
+    expect(result.probeSession).not.toBeNull();
+  });
+
+  it("throws immediately on a permanent zero-duration error (renderReady: true — genuine authoring bug)", async () => {
+    resetRetryMocks();
+    capturedCfgs.length = 0;
+    initializeSessionError = new Error(
+      "[FrameCapture] Composition has zero duration.\n  Runtime ready: true, __player: true, __hf.seek: true, GSAP timeline: false, data-duration: not set",
+    );
+    initializeSessionFailUntilAttempt = 999;
+
+    const { runProbeStage } = await import("./probeStage.js");
+    const input = makeProbeInput({ cfgForceScreenshot: false, stageForceScreenshot: false });
+
+    let caught: unknown;
+    try {
+      await runProbeStage(input);
+    } catch (err) {
+      caught = err;
+    }
+
+    expect(caught).toBeInstanceOf(Error);
+    expect((caught as Error).message).toContain("Runtime ready: true");
+    expect(initializeSessionCallCount).toBe(1);
+    expect(closeCaptureSessionCallCount).toBe(1);
+  });
+
   it("retries on a transient browser LAUNCH failure (createCaptureSession throws)", async () => {
     resetRetryMocks();
     capturedCfgs.length = 0;