feat(email): add admin notification settings

apps/backend/models/email_settings.py

@@ -0,0 +1,30 @@
+from __future__ import annotations
+
+from datetime import datetime
+
+from sqlalchemy import Boolean, DateTime, Integer, String
+from sqlalchemy.orm import Mapped, mapped_column
+from sqlalchemy.sql import func
+
+from backend.models.database import Base
+
+
+class EmailNotificationSettings(Base):
+    """系统邮件配置与通知策略设置。"""
+
+    __tablename__ = "email_notification_settings"
+
+    id: Mapped[int] = mapped_column(Integer, primary_key=True, default=1)
+    smtp_server: Mapped[str] = mapped_column(String(255), default="", nullable=False)
+    smtp_port: Mapped[int] = mapped_column(Integer, default=465, nullable=False)
+    smtp_sender_email: Mapped[str] = mapped_column(String(255), default="", nullable=False)
+    smtp_sender_password: Mapped[str] = mapped_column(String(500), default="", nullable=False)
+    smtp_use_ssl: Mapped[bool] = mapped_column(Boolean, default=True, nullable=False)
+    notify_token_expiring: Mapped[bool] = mapped_column(Boolean, default=True, nullable=False)
+    notify_check_in_success: Mapped[bool] = mapped_column(Boolean, default=True, nullable=False)
+    created_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True), server_default=func.now(), comment="创建时间"
+    )
+    updated_at: Mapped[datetime | None] = mapped_column(
+        DateTime(timezone=True), onupdate=func.now(), comment="更新时间"
+    )