# PRD · Core data model & storage

Implement IndexedDB schema, migrations, and API for CRUD and queries (unresolved-first).


## S1 · IndexedDB schema and CRUD

Acceptance:

- IndexedDB schema implements handover_item with required fields; records persist after browser restart.
- Automated test: write 3 items, reload page, query unresolved items and receive same 3 items.

## S2 · Unresolved-first query and migration

Acceptance:

- Query API returns items sorted: open and awaiting_review before closed; stable sorting by updated_at desc within status.
- Migration test: simulate older record without acknowledged_at; app upgrades schema without data loss.