[EPIC] Implement retained deletion for IRC tables

### Describe the proposal

After design approval, implement the accepted standard IRC `DELETE` behavior for retained deletion: capture recovery material, create a durable deletion record, deregister the backing Iceberg table without physical purge, and reserve the name during recovery.

When the feature is disabled or unsupported for a deployment mode, existing IRC delete behavior remains unchanged.

### Task list

- [ ] Implement the accepted standard-delete interception and lifecycle handoff.
- [ ] Capture and validate approved recovery metadata.
- [ ] Enforce name reservation across create, register, and rename.
- [ ] Define and implement interruption/reconciliation boundaries.
- [ ] Add IRC end-to-end coverage in supported modes.

Depends on: #12393, #12394

Related to: #12392