feat: MTG database integration with Redis caching

- Added MTG card ORM models (mtg_cards, mtg_sets tables)
- Created card_database service with search, get_by_name, get_by_set
- Added Redis client with caching layer (3600s TTL default)
- Created card router with caching on all endpoints:
  - Search cards (5min cache)
  - Get card by name (10min cache)
  - Get cards by set (15min cache)
  - Get card types/rarities (30min cache)
  - Get sets (1hr cache)
  - Get statistics (1hr cache)
- Updated settings.py:
  - Added JWT_SECRET_KEY field
  - Added DB_CONFIG and REDIS_CONFIG dictionaries
- Updated security.py to use JWT_SECRET_KEY with fallback
- Updated auth.py to use timezone-aware datetimes
- Updated refresh_mtg.py to use settings instead of os.environ
- Updated mtg_monitor.py to use settings for connections
- Added services package with __init__.py

All 20 tests passing.

backend/app/routers/decks.py

@@ -171,77 +171,6 @@ async def delete_folder(
     return {"message": "Folder deleted successfully"}
 
 
-@router.get("/", response_model=List[DeckResponse])
-async def list_decks(
-    folder_id: Optional[int] = None,
-    page: int = 1,
-    page_size: int = 50,
-    db: AsyncSession = Depends(get_db),
-    current_user: dict = Depends(get_current_user),
-):
-    """List decks for current user."""
-    user_id = int(current_user["user_id"])
-    
-    if folder_id:
-        stmt = (
-            select(DecklistFile)
-            .where(
-                DecklistFile.owner_id == user_id,
-                DecklistFile.folder_id == folder_id,
-            )
-            .offset((page - 1) * page_size)
-            .limit(page_size)
-        )
-    else:
-        stmt = (
-            select(DecklistFile)
-            .where(DecklistFile.owner_id == user_id)
-            .offset((page - 1) * page_size)
-            .limit(page_size)
-        )
-    
-    result = await db.execute(stmt)
-    decks = result.scalars().all()
-    
-    return [DeckResponse.model_validate(deck) for deck in decks]
-
-
-@router.post("/", response_model=DeckResponse)
-async def create_deck(
-    request: DeckCreate,
-    db: AsyncSession = Depends(get_db),
-    current_user: dict = Depends(get_current_user),
-):
-    """Create a new deck."""
-    user_id = int(current_user["user_id"])
-    
-    # Verify folder exists if specified
-    if request.folder_id:
-        stmt = select(DecklistFolder).where(
-            DecklistFolder.id == request.folder_id,
-            DecklistFolder.owner_id == user_id,
-        )
-        result = await db.execute(stmt)
-        folder = result.scalar_one_or_none()
-        if not folder:
-            raise HTTPException(
-                status_code=status.HTTP_404_NOT_FOUND,
-                detail="Folder not found",
-            )
-    
-    new_deck = DecklistFile(
-        owner_id=user_id,
-        folder_id=request.folder_id,
-        name=request.name,
-        content=request.content,
-        format=request.format,
-    )
-    db.add(new_deck)
-    await db.flush()
-    
-    return DeckResponse.model_validate(new_deck)
-
-
 @router.get("/{deck_id}", response_model=DeckResponse)
 async def get_deck(
     deck_id: int,