Davy7/20/2026, 8:11:13 PM

- record_prepared_operation now uses a unique timestamp-based id
  (publish-batch-<ms>) for batch mutations instead of the constant
  publish-batch, preventing primary-key collisions across sequential
  or concurrent mutations.
- get_all_upload_statuses filters out Publish rows whose payload has
  empty song_ids. These batch placeholder rows are internal outbox
  bookkeeping for recovery; surfacing them produced a phantom Running
  upload entry that never completed and persisted across restarts.
- The in-memory control DB fallback (when the file-backed DB fails to
  open) now applies remote-state migrations so recovery and upload-status
  queries do not hit no-such-table errors in degraded mode.

Parent509762a