feat(v1.1.9): dispatcher queue arm + visibility-timeout reclaim task

Extends Dispatcher with the v1.1.9 queue path. The queue table IS the
outbox for queue semantics, so the dispatcher polls queue_messages
directly via FOR UPDATE SKIP LOCKED — no outbox indirection.

Per tick (every 100ms):
  1) outbox arm — unchanged
  2) queue arm: list_active_queue_consumers() → per (app_id, queue_name)
     attempt one claim. Bounded by registered-consumer count so one busy
     queue can't starve others.

Per claimed message:
  - Build TriggerEvent::Queue + ExecRequest (executes as the trigger's
    registering principal, matching design notes §4)
  - dispatch through executor.execute_with_identity (reuses AST cache)
  - success → queue.ack(id, claim_token) — DELETE WHERE id AND token
  - throw + attempt < max_attempts → queue.nack(...) — clear claim, set
    deliver_after = NOW() + compute_backoff(attempt, backoff, base_ms, jitter)
  - throw + exhausted → queue.dead_letter(...) atomic move to dead_letters
    + DELETE in one transaction. fan_out_dead_letter on the outbox arm
    fires registered dead_letter handlers off the new row without changes.

Visibility-timeout reclaim task: separate tokio::spawn ticking on
queue_reclaim_interval_ms (default 30000). UPDATE clears claim_token /
claimed_at on rows whose claimed_at exceeds the per-queue
visibility_timeout_secs (joined from queue_trigger_details). A crashed
consumer thus loses its lease and the message becomes claimable again.

Dispatcher gains queue: Arc<dyn QueueRepo>; picloud/lib.rs threads
queue_repo.clone() into the construction.

ActiveQueueConsumer extended with app_id so the queue claim can be
performed without a follow-up trigger lookup; list_active_queue_consumers
SQL extended to SELECT t.app_id.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

crates/picloud/src/lib.rs

@@ -344,6 +344,7 @@ pub async fn build_app(
         executor: executor.clone(),
         gate,
         inbox: inbox_resolver,
+        queue: queue_repo.clone(),
         config: trigger_config,
         instance_id: format!("picloud-{}", std::process::id()),
     }