feat(email): add admin notification settings

apps/backend/schemas/email_settings.py

@@ -0,0 +1,57 @@
+from __future__ import annotations
+
+from datetime import datetime
+
+from email_validator import EmailNotValidError, validate_email
+from pydantic import BaseModel, ConfigDict, Field, field_validator
+
+
+class EmailNotificationSettingsBase(BaseModel):
+    smtp_server: str = Field("", max_length=255, description="SMTP 服务器地址")
+    smtp_port: int = Field(465, ge=1, le=65535, description="SMTP 端口")
+    smtp_sender_email: str = Field("", max_length=255, description="发件邮箱")
+    smtp_use_ssl: bool = Field(True, description="是否使用 SMTP SSL")
+    notify_token_expiring: bool = Field(True, description="是否通知 Token 即将过期")
+    notify_check_in_success: bool = Field(True, description="是否通知打卡成功")
+
+    @field_validator("smtp_server", "smtp_sender_email", mode="before")
+    @classmethod
+    def strip_text(cls, value: object) -> object:
+        if isinstance(value, str):
+            return value.strip()
+        return value
+
+    @field_validator("smtp_sender_email")
+    @classmethod
+    def validate_sender_email(cls, value: str) -> str:
+        if value == "":
+            return value
+        try:
+            return str(validate_email(value, check_deliverability=False).normalized)
+        except EmailNotValidError as exc:
+            raise ValueError("发件邮箱格式无效") from exc
+
+
+class EmailNotificationSettingsUpdate(EmailNotificationSettingsBase):
+    smtp_sender_password: str | None = Field(
+        None,
+        max_length=500,
+        description="新 SMTP 密码；省略表示保留现有值",
+    )
+    clear_smtp_sender_password: bool = Field(False, description="是否清空 SMTP 密码")
+
+    @field_validator("smtp_sender_password")
+    @classmethod
+    def normalize_password(cls, value: str | None) -> str | None:
+        if value == "":
+            return None
+        return value
+
+
+class EmailNotificationSettingsResponse(EmailNotificationSettingsBase):
+    model_config = ConfigDict(from_attributes=True)
+
+    id: int
+    has_smtp_sender_password: bool
+    created_at: datetime | None = None
+    updated_at: datetime | None = None