Function spawn_docker_log_stream 

pub fn spawn_docker_log_stream(
    docker: Docker,
    container_id: String,
    service_name: String,
    store: Arc<RwLock<TelemetryStore>>,
    events_tx: Sender<TelemetryEvent>,
    cancel: CancellationToken,
    tracker: &TaskTracker,
)

Spawn a background task that streams Docker container logs into the TelemetryStore and broadcasts them over WebSocket.

Only captures new logs produced after the stream starts (since: now). The task exits cleanly when cancel fires or the container stops.