Implement Phase B: Crash Recovery
Add startup integrity checks, corruption recovery, CAS size limits,
graceful shutdown orchestration, and a task supervisor — turning 5
previously-RED resilience tests GREEN and adding 5 new tests.
- CAS: pre-check size limit in put(), add StoreFull error variant
- CAS: sled corruption recovery in open() (retry then recreate)
- SQLite: open_with_integrity_check() via PRAGMA integrity_check(1)
- tantivy: open_with_recovery() deletes and rebuilds corrupt index
- CLI: CancellationToken-based ordered shutdown sequence
- Core: TaskSupervisor with spawn_supervised/spawn_critical + backoff
- Tests: replace 4 todo!() stubs, add 5 new shutdown/supervisor tests
Alexander
5da96ffab2