Method createPersistentVideoElement

app/src/utils/streamManager.ts:328–374

* Create a persistent video element that stays attached to a stream. * Waits for the video to be fully ready (first frame rendered) before resolving. * This eliminates race conditions on frame capture, especially on iOS.

(stream: MediaStream, timeoutMs: number = 5000)

   * This eliminates race conditions on frame capture, especially on iOS.
   */
  private async createPersistentVideoElement(stream: MediaStream, timeoutMs: number = 5000): Promise<HTMLVideoElement> {
    const video = document.createElement('video');
    video.srcObject = stream;
    video.muted = true;
    video.playsInline = true;

    // Wait for video to be ready with first frame
    await new Promise<void>((resolve, reject) => {
      const timeout = setTimeout(() => {
        Logger.warn("StreamManager", "Video element ready timeout - proceeding anyway");
        resolve();
      }, timeoutMs);

      const checkReady = () => {
        // readyState >= 2 (HAVE_CURRENT_DATA) means we have at least one frame
        if (video.readyState >= 2 && video.videoWidth > 0) {
          clearTimeout(timeout);
          resolve();
          return true;
        }
        return false;
      };

      // Check if already ready
      if (checkReady()) return;

      // Listen for loadeddata event (fires when first frame is available)
      video.addEventListener('loadeddata', () => {
        if (checkReady()) return;
      }, { once: true });

      // Also listen for canplay as fallback
      video.addEventListener('canplay', () => {
        if (checkReady()) return;
      }, { once: true });

      // Start playing
      video.play().catch(e => {
        Logger.warn("StreamManager", `Video play failed: ${e}`);
        clearTimeout(timeout);
        reject(e);
      });
    });

    Logger.debug("StreamManager", `Video element ready: readyState=${video.readyState}, ${video.videoWidth}x${video.videoHeight}`);
    return video;
  }

  /**
   * Capture a frame from a video stream. Returns base64 PNG or null.