Davy7/21/2026, 9:59:55 AM

Close remaining #175 P0/P1 protocol gaps:

- Manifest carries operation_id; accepted-commit requires operation match
  plus durable candidate digest/size (never claim CAS after coalesce clear)
- CAS-boundary ops (frozen/uploaded candidate) reconcile alone — not coalesced
- Import resolves working copy only from prepared.library_id
- bind_song_ids_mark_pending_and_dirty_tx rejects library_id mismatch
- Coalesce skips rate-limited RetryWait; preserves max next_attempt_at_ms
- Per-library commit lock covers pre-mutation refresh + prepare + mutate + project

Parent4f88cf1