Function run_posting_queue 

pub async fn run_posting_queue(
    receiver: Receiver<PostAction>,
    executor: Arc<dyn PostExecutor>,
    min_delay: Duration,
    cancel: CancellationToken,
)

Run the posting queue consumer loop.

Processes actions sequentially with min_delay between each post. On cancellation, drains remaining actions in the channel before exiting.

When approval_queue is Some, actions are queued for human review instead of being posted directly.