feat: Airwallex 发卡管理后台完整实现

- 后端: FastAPI + SQLAlchemy + SQLite, JWT认证, 代理支持的AirwallexClient
- 前端: React 18 + Vite + Ant Design 5, 中文界面
- 功能: 卡片管理, 持卡人管理, 交易记录, API令牌, 系统设置, 审计日志
- 第三方API: X-API-Key认证, 权限控制
- Docker部署: docker-compose编排前后端

backend/app/database.py

@@ -0,0 +1,35 @@
+"""Database setup and session management."""
+from typing import Generator
+
+from sqlalchemy import create_engine
+from sqlalchemy.orm import DeclarativeBase, Session, sessionmaker
+
+from .config import settings
+
+
+engine = create_engine(
+    settings.DATABASE_URL,
+    connect_args={"check_same_thread": False},  # SQLite specific
+    echo=False,
+)
+
+SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)
+
+
+class Base(DeclarativeBase):
+    """Declarative base for all ORM models."""
+    pass
+
+
+def get_db() -> Generator[Session, None, None]:
+    """FastAPI dependency that provides a database session."""
+    db = SessionLocal()
+    try:
+        yield db
+    finally:
+        db.close()
+
+
+def create_tables() -> None:
+    """Create all database tables."""
+    Base.metadata.create_all(bind=engine)