Update CLAUDE.md TODO list and add local-first documentation

- Consolidate UI TODO items into single sync status partial task
- Move conflict resolution to Phase 4
- Add LOCAL_FIRST_INTEGRATION.md with architecture guide
- Add unified repository interface for future use

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

CLAUDE.md

@@ -31,11 +31,9 @@
 - ✅ Background sync worker: auto-sync every 5min (push + pull) - `internal/services/sync/worker.go`
 
 **TODO:**
-- ❌ Conflict resolution (last-write-wins or manual)
-- ❌ UI: pending counter in header
-- ❌ UI: manual sync button
-- ❌ UI: offline indicator (middleware already exists)
+- ❌ UI: sync status partial (pending badge + sync button + offline indicator)
 - ❌ RefreshPrices for local mode (via local_components)
+- ❌ Conflict resolution (Phase 4, last-write-wins default)
 
 ### Phase 3: Projects and Specifications
 - qt_projects, qt_specifications tables (MariaDB)