优化登录任务界面 + 修复时间显示 + 增加删除功能

- 筛选栏改为单行横排，概览精简为一行文字
- 任务列表全宽展示，日志移到底部可折叠
- 页面使用百分比布局，一屏展示无外层滚动
- 登录任务增加单条删除和批量删除功能
- 后端: datetime.utcnow 替换为 datetime.now(timezone.utc)
- 后端: schemas 序列化统一输出带时区 ISO 格式
- 前端: 新增 utils/time.ts 统一时间格式化工具
- 前端: CookiePage/LoginTasksPage 时间列使用 formatTime()

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

web/backend/schemas.py

@@ -1,8 +1,17 @@
 """Pydantic 请求/响应模型"""
 
-from datetime import datetime
-from typing import Optional
-from pydantic import BaseModel, Field
+from datetime import datetime, timezone
+from typing import Optional, Any
+from pydantic import BaseModel, Field, ConfigDict, model_serializer
+
+
+def _ensure_tz(dt: Optional[datetime]) -> Optional[datetime]:
+    """确保 datetime 带有 UTC 时区信息，无时区的视为 UTC。"""
+    if dt is None:
+        return None
+    if dt.tzinfo is None:
+        return dt.replace(tzinfo=timezone.utc)
+    return dt
 
 
 # ---- 认证 ----
@@ -29,8 +38,20 @@ class UserInfo(BaseModel):
     permissions: list[str] = []
     custom_permissions: Optional[list[str]] = None
 
-    class Config:
-        from_attributes = True
+    model_config = ConfigDict(from_attributes=True)
+
+    @model_serializer
+    def _serialize(self) -> dict[str, Any]:
+        return {
+            "id": self.id,
+            "username": self.username,
+            "role": self.role,
+            "is_active": self.is_active,
+            "remark": self.remark,
+            "created_at": _ensure_tz(self.created_at).isoformat() if self.created_at else None,
+            "permissions": self.permissions,
+            "custom_permissions": self.custom_permissions,
+        }
 
 
 # ---- 用户管理 ----
@@ -82,8 +103,22 @@ class AccountOut(BaseModel):
     remark: str = ""
     created_at: Optional[datetime] = None
 
-    class Config:
-        from_attributes = True
+    model_config = ConfigDict(from_attributes=True)
+
+    @model_serializer
+    def _serialize(self) -> dict[str, Any]:
+        return {
+            "id": self.id,
+            "username": self.username,
+            "password": self.password,
+            "email": self.email,
+            "email_password": self.email_password,
+            "tag": self.tag,
+            "assigned_to": self.assigned_to,
+            "assigned_username": self.assigned_username,
+            "remark": self.remark,
+            "created_at": _ensure_tz(self.created_at).isoformat() if self.created_at else None,
+        }
 
 
 # ---- 登录任务 ----
@@ -105,8 +140,22 @@ class LoginTaskOut(BaseModel):
     created_at: Optional[datetime] = None
     finished_at: Optional[datetime] = None
 
-    class Config:
-        from_attributes = True
+    model_config = ConfigDict(from_attributes=True)
+
+    @model_serializer
+    def _serialize(self) -> dict[str, Any]:
+        return {
+            "id": self.id,
+            "batch_id": self.batch_id,
+            "account_id": self.account_id,
+            "account_username": self.account_username,
+            "status": self.status,
+            "cookie": self.cookie,
+            "message": self.message,
+            "created_by": self.created_by,
+            "created_at": _ensure_tz(self.created_at).isoformat() if self.created_at else None,
+            "finished_at": _ensure_tz(self.finished_at).isoformat() if self.finished_at else None,
+        }
 
 
 # ---- 代理配置 ----