Integrate ai.card Rust API with ai.gpt MCP and implement daily limit system

### Major Changes:
- **Rust Migration**: Move api-rs to root directory, rename binary to 'aicard'
- **MCP Integration**: Add card tools to ai.gpt MCP server (get_user_cards, draw_card, get_draw_status)
- **Daily Limit System**: Implement 2-day interval card drawing limits in API and iOS
- **iOS Enhancements**: Add DrawStatusView, backup functionality, and limit integration

### Technical Details:
- ai.gpt MCP now has 20 tools including 3 card-related tools
- ServiceClient enhanced with missing card API methods
- iOS app includes daily limit UI and atproto OAuth backup features
- Database migration for last_draw_date field
- Complete feature parity between web and iOS implementations

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

python/api/app/services/gacha.py

@@ -34,7 +34,19 @@ class GachaService:
             
         Returns:
             (Card, is_unique): 抽選されたカードとuniqueかどうか
+            
+        Raises:
+            ValueError: If user cannot draw due to daily limit
         """
+        # Check if user can draw (daily limit)
+        can_draw = await self.user_repo.can_draw_card(user_did, settings.draw_limit_days)
+        if not can_draw:
+            next_draw_time = await self.user_repo.get_next_draw_time(user_did, settings.draw_limit_days)
+            if next_draw_time:
+                raise ValueError(f"カードを引けるのは{next_draw_time.strftime('%Y-%m-%d %H:%M:%S')}以降です。")
+            else:
+                raise ValueError("現在カードを引くことができません。")
+        
         # Get or create user
         user = await self.user_repo.get_or_create(user_did)
         # レアリティ抽選
@@ -78,6 +90,9 @@ class GachaService:
         )
         self.session.add(draw_history)
         
+        # Update user's last draw date
+        await self.user_repo.update_last_draw_date(user.id)
+        
         # API用のCardモデルに変換
         card = Card(
             id=card_id,