fix(docs): correct Phase 9 completion document

Clarify that OPDS, book matching, and conflict resolution were
already implemented in earlier phases (3, 5, 6), not future
enhancements.

All three features are fully functional:
- Phase 3: Universal Book Matching Engine ✅
- Phase 5: OPDS Implementation ✅
- Phase 6: Enhanced Kobo Sync with Conflict Resolution ✅

PHASE_9_COMPLETION.md

@@ -244,12 +244,32 @@
 3. **Search**: Full-text search not integrated with collections
 4. **Real-time Updates**: WebSocket integration for live updates pending
 
+### ✅ Already Implemented (Previous Phases)
+The following features are **COMPLETE** and were implemented in earlier phases:
+1. **OPDS Integration**: ✅ Complete (Phase 5) - `internal/handlers/opds.go`
+   - OPDS catalog feeds per device
+   - Format conversion (EPUB → KEPUB)
+   - ContentId mapping
+   - Wireless book delivery
+
+2. **Advanced Book Matching**: ✅ Complete (Phase 3) - `internal/handlers/book_matching.go`
+   - Multi-identifier matching (UUID, SHA-256, ISBN, OPF)
+   - Confidence scoring algorithm
+   - Manual linking interface
+   - Unlinked book detection
+
+3. **Conflict Resolution**: ✅ Complete (Phase 6) - `internal/handlers/conflicts.go`
+   - Automatic conflict detection
+   - Manual merge UI (`templates/conflicts.templ`)
+   - Winner selection (Kobo, KOReader, Web, Manual)
+   - WebSocket notifications
+
 ### Future Enhancements (Phase 10+)
-1. **OPDS Integration**: Wireless book delivery (Phase 5)
-2. **Advanced Matching**: ML-based book matching (Phase 3)
-3. **Conflict Resolution**: UI for progress merge decisions (Phase 6)
-4. **Analytics**: Reading statistics and insights
-5. **Export**: Collection export to OPML/JSON
+1. **Analytics**: Reading statistics and insights dashboard
+2. **Export**: Collection export to OPML/JSON formats
+3. **Social**: Share reading progress with friends
+4. **Recommendations**: AI-powered book recommendations
+5. **Advanced Search**: Full-text search with filters
 
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