Function run_chunk_encoder_worker_blocking 

pub fn run_chunk_encoder_worker_blocking(
    cfg: EncoderWorkerConfig,
    queue: Arc<SegmentChunkQueue>,
    rt: Handle,
    shared_frames_encoded: Arc<AtomicU64>,
    progress_tx: Sender<u64>,
    out: Arc<Mutex<Vec<ChunkPackets>>>,
) -> Result<()>

Encoder worker that COLLECTS packets per chunk (single-file path). Each chunk is encoded by a fresh encoder (first frame an IDR); the cross-vendor codec invariant is enforced on the first packet (mismatch → requeue + exit, exactly like the CMAF worker). Ordered ChunkPackets are pushed to out.