Phase 3: Schema Layer - Pydantic v2 migration, deduplication, and missing schemas

- Migrated all schemas to Pydantic v2 syntax (model_config, ConfigDict)
- Fixed mutable default in ProtoMessageBase using Field(default_factory=datetime.now)
- Consolidated CardCollection and Wishlist schemas in user_card_collection.py
- Created game_schemas.py with GameCreate, GameResponse, GameJoinRequest, etc.
- Created mtg_card_schemas.py with MtgCardResponse, MtgCardSearchRequest, etc.
- Added CardImportBatchCreate, CardImportBatchResponse, UserCardImportCreate/Response schemas
- Fixed duplicate UserCardImportRecord class between card_import_batch.py and user_card_import_record.py
- Updated __init__.py with comprehensive schema exports
- Created verify_schemas.py for schema-model matching verification

backend/app/models/models.py

@@ -80,8 +80,21 @@ class MtgonlineCard(Base):
     synced_at = Column(DateTime, server_default=func.now(), onupdate=func.now())
     created_at = Column(DateTime, server_default=func.now())
     
+    # Relationships
+    deck_cards = relationship(
+        "UserDeckCard",
+        back_populates="card",
+        cascade="all, delete-orphan"
+    )
+    
+    # Indexes
+    __table_args__ = (
+        Index('idx_mtgonline_cards_name', 'name'),
+        Index('idx_mtgonline_cards_set', 'set_code'),
+    )
+    
     def __repr__(self) -> str:
-        return f"<MtonlineCard {self.name} (ID: {self.id}, source: {self.source_id})>"
+        return f"<MtgonlineCard {self.name} (ID: {self.id}, source: {self.source_id})>"
 
 
 class DecklistFolder(Base):
@@ -99,6 +112,11 @@ class DecklistFolder(Base):
     children = relationship("DecklistFolder", back_populates="parent", cascade="all, delete-orphan")
     parent = relationship("DecklistFolder", back_populates="children", remote_side=[id])
     files = relationship("DecklistFile", back_populates="folder", cascade="all, delete-orphan")
+    user_decks = relationship(
+        "UserDeck",
+        back_populates="folder",
+        lazy="select"
+    )
 
 
 class DecklistFile(Base):