feat(orch): Consume hook events

[prathshenoy]

Summary

What:

• Consume lifecycle events from the queue and hand each one to the integration the deployment wires, accepting and discarding them while no integration is attached.
• Reconcile the matching dead-letter queue so events that fail every retry are recorded and alerted on instead of accumulating unread.

Why:

• Prove the delivery path end to end before anything produces an event, so a later change adds producers to a route that already works.
• Keep a deployment with no integrations configured distinguishable from one that is silently losing events.

Test Plan

• Add unit tests.

Revert Plan

• Revert this PR. Since nothing publishes hook events yet and the wired hook is a no-op, no side effect is lost.

Issues

• CODEM-416

Stack

1. feat(hook): Add contract for lifecycle events #606
2. feat(hook): Deliver events to integrations #607
3. @ feat(orch): Consume hook events #608