feat: production branch with deploy config for baota panel

- Add deploy/ directory with production env, supervisor, nginx, migration configs
- Include all latest features: admin management, feedback, footer with ICP/beian
- Database: foreign_trade (PostgreSQL), user: foreign_trade
- Frontend: trade.yuzhiran.com, backend proxy via Nginx

backend/app/models/user.py

@@ -17,6 +17,9 @@ class User(Base):
     tier = Column(String(50), default="free")
     role = Column(String(20), default="user")
     is_active = Column(Boolean, default=True)
+    email = Column(String(255))
+    last_login_at = Column(DateTime, nullable=True)
+    login_count = Column(Integer, default=0)
     created_at = Column(DateTime, default=datetime.utcnow)
     updated_at = Column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)
     settings = Column(JSONB, default={