feat: add support for pagination responses

also fix check-in error messages not displaying

backend/schemas/check_in.py

@@ -1,7 +1,9 @@
 from datetime import datetime
-from typing import Optional
+from typing import Optional, List, Generic, TypeVar
 from pydantic import BaseModel, Field, ConfigDict
 
+T = TypeVar('T')
+
 
 class ManualCheckInRequest(BaseModel):
     """手动打卡请求 Schema（已废弃，现在使用路径参数 task_id）"""
@@ -46,3 +48,11 @@ class CheckInResultResponse(BaseModel):
     message: str
     record_id: Optional[int] = None
     error: Optional[str] = None
+
+
+class PaginatedResponse(BaseModel, Generic[T]):
+    """分页响应 Schema"""
+    records: List[T] = Field(..., description="记录列表")
+    total: int = Field(..., description="总记录数")
+    skip: int = Field(..., description="跳过的记录数")
+    limit: int = Field(..., description="每页记录数")