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

backend/app/routers/__init__.py

@@ -13,6 +13,7 @@ from app.routers import admin
 from app.routers import card_router
 from app.routers import interactions
 from app.routers import refresh
+from app.routers import card_import
 
 __all__ = [
     "auth",
@@ -24,4 +25,5 @@ __all__ = [
     "card_router",
     "interactions",
     "refresh",
+    "card_import",
 ]