Serialize AnalysisNwbfile.cleanup and make trigger ownership explicit

[edeno]

Follow-up to #1574.

AnalysisNwbfile.cleanup() currently documents a single-cleanup-process
contract. Trigger creation/removal is not owned by a run: overlapping runs can
adopt and remove one another's triggers, a partial acquisition can leave
inserts blocked, and registry changes can strand triggers.

Acceptance criteria

• Serialize cleanup with a MySQL advisory lock or equivalent database-wide
  lease.
• Reject or explicitly recover from pre-existing/stale cleanup triggers.
• Have trigger acquisition return the exact triggers created by this run.
• Roll back only those owned triggers after partial acquisition failure.
• Drop only owned triggers during normal release.
• Preserve the original cleanup exception while making release failures loud.
• Add DB-backed tests for overlap, pre-existing triggers, partial acquisition,
  registry changes, and stale recovery instructions.

This issue covers cleanup-run ownership, not the separate writer-registration
race.