- Add compaction_snapshots table to schema with proper indexes - Implement CreateSnapshot, RestoreFromSnapshot, GetSnapshots functions - Use UTC timestamps throughout - RestoreFromSnapshot uses transactions with optimistic concurrency control - Add validation for levels and issue_id matching - Prevent race conditions with compaction_level guard - Create bd-268 to explore lightweight SQL alternatives Amp-Thread-ID: https://ampcode.com/threads/T-3bdd0d6b-9212-4e4e-b22d-f658949df7a9 Co-authored-by: Amp <amp@ampcode.com>