[Subtask]: Activate and validate the View metadata lifecycle

### Parent Issue

Parent issue: #26227

### Detail of Subtask

Activate the complete View metadata lifecycle and provide end-to-end rolling-upgrade, restore, and rollback evidence.

Deliverables:

- Connect the HAKeeper barrier, durable catalog recovery, and CN/frontend metadata authority paths.
- Enable the final-version rollout sequence only after exact catalog readiness and capability predicates are satisfied.
- Complete DDL integration so dependency changes regenerate the full authoritative View schema atomically.
- Mixed-binary sequence covering all-old, partial upgrade, all-new activation, restart, same-UUID replacement, rollback denial, recovery, and immediate cluster restart.
- Two-CN shared-catalog restore barrier and public SQL/BVT coverage.
- Rollout, observability, rollback, and conformance documentation.

Acceptance criteria:

- `DESC`, `information_schema.columns`, direct View queries, and CTAS expose one consistent current schema.
- No reader admitted after invalidation/restore commit can return stale View metadata.
- Unsupported binaries cannot author or expose the new lifecycle state.
- All owning-package normal/race tests, focused coverage, BVT, mixed-binary evidence, and teardown checks pass.
- The final semantic checkpoint and conformance head receive traceable design and implementation approval.

### Describe implementation you've considered

Use the ordered rollout: catalog ready, capabilities proven, membership epoch advanced, metadata readers sealed, durable required generation published, recovery completed, authority reopened, and only then allow new-protocol authoring.

### Additional information

Final activation phase for #26227. Depends on all preceding subtasks.