Initial commit: TradeMate 外贸小助手 MVP

项目结构:
- backend/     Python FastAPI 后端
- uni-app/     uni-app跨端前端
- docs/        设计文档
- docker-compose.yml  Docker编排
- nginx/scripts/systemd 运维配置

已完成功能:
- 用户认证 (JWT)
- 智能翻译 + 回复建议
- 营销素材生成
- 客户管理 + 沉默检测
- 报价单管理
- 产品库管理
- 汇率换算
- 推送通知 (uni-push)
- WhatsApp Webhook框架
- Celery定时任务

backend/app/database.py

@@ -0,0 +1,33 @@
+from sqlalchemy.ext.asyncio import AsyncSession, create_async_engine
+from sqlalchemy.orm import sessionmaker, declarative_base
+from app.config import settings
+
+async_engine = create_async_engine(
+    settings.DATABASE_URL,
+    echo=settings.DB_ECHO,
+    pool_size=20,
+    max_overflow=10,
+    pool_pre_ping=True,
+)
+
+AsyncSessionLocal = sessionmaker(
+    async_engine,
+    class_=AsyncSession,
+    expire_on_commit=False,
+    autocommit=False,
+    autoflush=False,
+)
+
+Base = declarative_base()
+
+
+async def get_db() -> AsyncSession:
+    async with AsyncSessionLocal() as session:
+        try:
+            yield session
+            await session.commit()
+        except Exception:
+            await session.rollback()
+            raise
+        finally:
+            await session.close()