- Add GET /api/reports/last-sync endpoint to query server for last sync information
- Update reports page with sorting by client name and cap balance
- Create comprehensive client-side implementation guide (CLIENT_SYNC_IMPLEMENTATION_GUIDE.md)
- Create minimal client prompt (CLIENT_SYNC_MINIMAL_PROMPT.md)
- Update final implementation documentation (REPORTS_FINAL_IMPLEMENTATION.md)

This allows clients to:
- Query server for last sync information before syncing
- Verify local tracking against server state
- Recover from tracking corruption
- Prevent data loss from missed syncs