feat: add card import feature with fuzzy matching

- Add UserCardImport model (stores imported card names as JSON)
- Create card_import_schemas.py with request/response models
- Create card_import.py router with import/get/delete endpoints
- Add Alembic migration 004 (user_card_imports table)
- Fuzzy matching for card name matching (60% threshold)
- Integration with deckbuilding via imported cards
- Endpoints: GET /api/v1/card-import/status, POST /, DELETE /, GET /summary

state.json

@@ -117,6 +117,6 @@
     "Phase 5: Deck builder service for precedents and suggestions"
   ],
   "blockers": [],
-  "commit_hash": "6b38ef0",
+  "commit_hash": "c23f88c",
   "timestamp": "2026-07-24T04:12:00-04:00"
 }