新增PDF生成并发设置

backend/app/models/setting.py

@@ -0,0 +1,15 @@
+from datetime import datetime
+
+from sqlalchemy import DateTime, String, Text
+from sqlalchemy.orm import Mapped, mapped_column
+
+from app.db.base import Base
+
+
+class SystemSetting(Base):
+    __tablename__ = "system_settings"
+
+    key: Mapped[str] = mapped_column(String(128), primary_key=True)
+    value: Mapped[str] = mapped_column(Text)
+    description: Mapped[str | None] = mapped_column(String(255), nullable=True)
+    updated_at: Mapped[datetime] = mapped_column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)