- snapshot_then() brackets all 19 mutating dispatch arms: stage a
pre-op snapshot, finalise on success / discard on rollback; gated
on a user command source (internal ops like open-time rebuild are
not snapshotted) and on undo being enabled
- BatchState + BeginBatch/EndBatch requests: a batch takes one
boundary snapshot, suppresses per-command snapshots, and finalises
iff a mutation committed (one undo step per replay/batch)
- Undo/Redo/PeekUndo/PeekRedo requests handled in worker_loop with
&mut conn for the restore; cleanup() sweeps crash leftovers on open
- Database::{undo,redo,peek_undo,peek_redo,begin_batch,end_batch} +
open_with_persistence_and_undo(); snapshot failures are non-fatal
(logged), restore failures surface
- 6 Tier-3 integration tests through the real worker
1680 passed / 0 failed / 1 ignored; clippy clean.