Add complete ai.card Rust implementation

- Implement complete Rust API server with axum framework
- Add database abstraction supporting PostgreSQL and SQLite
- Implement comprehensive gacha system with probability calculations
- Add JWT authentication with atproto DID integration
- Create card master data system with rarities (Normal, Rare, SuperRare, Kira, Unique)
- Implement draw history tracking and collection management
- Add API endpoints for authentication, card drawing, and collection viewing
- Include database migrations for both PostgreSQL and SQLite
- Maintain full compatibility with Python API implementation
- Add comprehensive documentation and development guide

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

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

python/api/app/db/__init__.py

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+# Database Package

python/api/app/db/base.py

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+"""Database base configuration"""
+import os
+from pathlib import Path
+from sqlalchemy.ext.declarative import declarative_base
+from sqlalchemy.ext.asyncio import AsyncSession, create_async_engine, async_sessionmaker
+from app.core.config import settings
+
+# Create base class for models
+Base = declarative_base()
+
+# Ensure database directory exists
+db_path = Path.home() / ".config" / "syui" / "ai" / "card"
+db_path.mkdir(parents=True, exist_ok=True)
+
+# Select database URL based on configuration
+database_url = settings.database_url_supabase if settings.use_supabase else settings.database_url
+
+# Expand ~ in database URL
+if database_url.startswith("sqlite"):
+    database_url = database_url.replace("~", str(Path.home()))
+
+# Create async engine (SQLite-optimized settings)
+if "sqlite" in database_url:
+    engine = create_async_engine(
+        database_url,
+        echo=settings.debug,
+        future=True,
+        # SQLite-specific optimizations
+        connect_args={"check_same_thread": False}
+    )
+else:
+    # PostgreSQL settings (fallback)
+    engine = create_async_engine(
+        database_url,
+        echo=settings.debug,
+        future=True,
+        pool_pre_ping=True,
+        pool_size=5,
+        max_overflow=10
+    )
+
+# Create async session factory
+async_session = async_sessionmaker(
+    engine,
+    class_=AsyncSession,
+    expire_on_commit=False
+)
+
+
+async def get_session() -> AsyncSession:
+    """Dependency to get database session"""
+    async with async_session() as session:
+        yield session

python/api/app/db/models.py

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+"""Database models"""
+from datetime import datetime
+from sqlalchemy import (
+    Column, Integer, String, DateTime, Boolean, 
+    Float, ForeignKey, UniqueConstraint, Index,
+    Enum as SQLEnum
+)
+from sqlalchemy.dialects.postgresql import UUID
+from sqlalchemy.orm import relationship
+import uuid
+import enum
+
+from app.db.base import Base
+from app.models.card import CardRarity
+
+
+class User(Base):
+    """ユーザーモデル"""
+    __tablename__ = "users"
+    
+    id = Column(Integer, primary_key=True, index=True)
+    did = Column(String, unique=True, nullable=False, index=True)
+    handle = Column(String, nullable=True)
+    created_at = Column(DateTime, default=datetime.utcnow)
+    updated_at = Column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)
+    
+    # Relationships
+    cards = relationship("UserCard", back_populates="owner")
+    draws = relationship("DrawHistory", back_populates="user")
+
+
+class CardMaster(Base):
+    """カードマスタデータ"""
+    __tablename__ = "card_master"
+    
+    id = Column(Integer, primary_key=True)  # 0-15
+    name = Column(String, nullable=False)
+    base_cp_min = Column(Integer, nullable=False)
+    base_cp_max = Column(Integer, nullable=False)
+    color = Column(String, nullable=False)
+    description = Column(String)
+    
+    # Relationships
+    user_cards = relationship("UserCard", back_populates="card_info")
+
+
+class UserCard(Base):
+    """ユーザー所有カード"""
+    __tablename__ = "user_cards"
+    
+    id = Column(Integer, primary_key=True, index=True)
+    user_id = Column(Integer, ForeignKey("users.id"), nullable=False)
+    card_id = Column(Integer, ForeignKey("card_master.id"), nullable=False)
+    cp = Column(Integer, nullable=False)
+    status = Column(SQLEnum(CardRarity), nullable=False)
+    skill = Column(String, nullable=True)
+    obtained_at = Column(DateTime, default=datetime.utcnow)
+    is_unique = Column(Boolean, default=False)
+    unique_id = Column(UUID(as_uuid=True), nullable=True, unique=True)
+    
+    # Relationships
+    owner = relationship("User", back_populates="cards")
+    card_info = relationship("CardMaster", back_populates="user_cards")
+    
+    # Indexes
+    __table_args__ = (
+        Index('idx_user_cards', 'user_id', 'card_id'),
+    )
+
+
+class UniqueCardRegistry(Base):
+    """uniqueカードのグローバルレジストリ"""
+    __tablename__ = "unique_card_registry"
+    
+    id = Column(Integer, primary_key=True)
+    unique_id = Column(UUID(as_uuid=True), default=uuid.uuid4, unique=True, nullable=False)
+    card_id = Column(Integer, ForeignKey("card_master.id"), nullable=False)
+    owner_did = Column(String, ForeignKey("users.did"), nullable=False)
+    obtained_at = Column(DateTime, default=datetime.utcnow)
+    verse_skill_id = Column(String, nullable=True)  # ai.verse連携用
+    
+    # Unique constraint: 各card_idは1人のみ所有可能
+    __table_args__ = (
+        UniqueConstraint('card_id', name='unique_card_per_type'),
+    )
+
+
+class DrawHistory(Base):
+    """ガチャ履歴"""
+    __tablename__ = "draw_history"
+    
+    id = Column(Integer, primary_key=True, index=True)
+    user_id = Column(Integer, ForeignKey("users.id"), nullable=False)
+    card_id = Column(Integer, nullable=False)
+    status = Column(SQLEnum(CardRarity), nullable=False)
+    cp = Column(Integer, nullable=False)
+    is_paid = Column(Boolean, default=False)
+    drawn_at = Column(DateTime, default=datetime.utcnow)
+    
+    # Relationships
+    user = relationship("User", back_populates="draws")
+    
+    # Indexes
+    __table_args__ = (
+        Index('idx_draw_history_user', 'user_id', 'drawn_at'),
+    )
+
+
+class GachaPool(Base):
+    """ガチャプール（ピックアップ管理）"""
+    __tablename__ = "gacha_pools"
+    
+    id = Column(Integer, primary_key=True)
+    name = Column(String, nullable=False)
+    description = Column(String)
+    is_active = Column(Boolean, default=True)
+    start_at = Column(DateTime, nullable=False)
+    end_at = Column(DateTime, nullable=True)
+    pickup_card_ids = Column(String)  # JSON array of card IDs
+    rate_up_multiplier = Column(Float, default=1.0)
+    created_at = Column(DateTime, default=datetime.utcnow)