Phase 2.1: Card mirror system for deckbuilding features

- Created MtgCardMirror and DeckCardLink models in mirror_models.py
- Created card_mirror_service.py with sync_mirrors functionality
- Added sync_mirrors() method to mtgjson_manager.py
- Added mirror_get_db() dependency to database.py
- Added DecklistFile.status column (DRAUGHT/FINAL)
- Updated DeckCreate schema with status field
- Added DeckWithCardsResponse schema with card_count
- Updated deck router to query card mirrors and return card counts
- Added plain text deck content support

backend/app/models/models.py

@@ -72,6 +72,7 @@ class DecklistFile(Base):
     name = Column(String(255), nullable=False)
     content = Column(Text, nullable=False)  # Native XML or plain text deck format
     format = Column(String(50), default="native")  # 'native' or 'plain'
+    status = Column(String(20), default="DRAUGHT")  # 'DRAUGHT' or 'FINAL'
     creation_date = Column(DateTime, server_default=func.now())
     
     # Relationships