fix(P1): 时间字段返回带UTC时区标识，修复前端显示差8小时

- 新增 format_utc_datetime 工具函数，统一输出带 Z 后缀的 ISO 8601
- 成片库 generated_at: 无时区字符串 -> 带 Z 的 UTC 时间
- 素材库 created_at: 无时区字符串 -> 带 Z 的 UTC 时间
- 任务列表 created_at/updated_at: datetime类型 -> 带 Z 的字符串
- 前端 new Date() 自动转本地时间，无需额外处理

apps/api/app/api/routes/_helpers.py

@@ -1,5 +1,6 @@
 """路由层共享辅助函数 — 消除跨文件重复定义。"""
 
+from datetime import datetime, timezone
 from typing import Any
 
 from fastapi import HTTPException, status
@@ -122,3 +123,18 @@ def auto_select_video_assets(
     # 按创建时间降序（新素材在前）
     filtered_videos.sort(key=lambda a: a.created_at, reverse=True)
     return [a.id for a in filtered_videos]
+
+def format_utc_datetime(dt: datetime | None) -> str:
+    """将数据库读出的 UTC naive datetime 格式化为带时区的 ISO 8601 字符串。
+
+    数据库 DateTime 列不带时区信息，但存的是 UTC 时间。
+    直接 .isoformat() 输出无时区标识，前端会按本地时间解析，导致差 8 小时。
+    输出带 Z 后缀，前端 new Date() 自动转本地时间。
+    """
+    if dt is None:
+        return ""
+    if isinstance(dt, str):
+        return dt
+    if dt.tzinfo is None:
+        return dt.isoformat() + "Z"
+    return dt.astimezone(timezone.utc).isoformat().replace("+00:00", "Z")

apps/api/app/api/routes/assets.py

@@ -1,7 +1,7 @@
 import logging
 from typing import Any, Optional
 
-from app.api.routes._helpers import check_project_access
+from app.api.routes._helpers import check_project_access, format_utc_datetime
 from app.auth import AuthenticatedUser, get_current_user
 from app.core.storage import get_storage_service
 from app.dependencies import (
@@ -71,7 +71,7 @@ def _to_asset_response(item, storage_service=None) -> AssetResponse:
         status=item.status.value,
         classification_status=item.classification_status.value,
         quality_score=item.quality_score,
-        created_at=item.created_at.isoformat() if item.created_at else None,
+        created_at=format_utc_datetime(item.created_at),
         uploaded_by_user_id=item.uploaded_by_user_id,
         tag_ids=getattr(item, "tag_ids", []),
     )

apps/api/app/api/routes/task_center.py

@@ -1,6 +1,7 @@
 import logging
 from typing import Any
 
+from app.api.routes._helpers import format_utc_datetime
 from app.auth import AuthenticatedUser, get_current_user
 from app.core.celery_app import celery_app
 from app.core.task_enqueue import (
@@ -99,8 +100,8 @@ def _generation_task_to_user_response(task) -> UserTaskResponse:
         retryable=_status_value(task.status) == "failed",
         retry_count=task.retry_count or 0,
         source_id=task.id,
-        created_at=task.created_at,
-        updated_at=task.completed_at or task.started_at or task.created_at,
+        created_at=format_utc_datetime(task.created_at),
+        updated_at=format_utc_datetime(task.completed_at or task.started_at or task.created_at),
     )
 
 
@@ -119,8 +120,8 @@ def _generation_task_to_project_response(task) -> ProjectTaskResponse:
         retry_count=task.retry_count or 0,
         source_id=task.id,
         template_id=task.template_id,
-        created_at=task.created_at,
-        updated_at=task.completed_at or task.started_at or task.created_at,
+        created_at=format_utc_datetime(task.created_at),
+        updated_at=format_utc_datetime(task.completed_at or task.started_at or task.created_at),
     )
 
 
@@ -284,8 +285,8 @@ def list_project_tasks(
                     user_message=_humanize_task_error(job.error_message),
                     retryable=_status_value(job.status) == "failed",
                     source_id=job.id,
-                    created_at=job.created_at,
-                    updated_at=job.updated_at,
+                    created_at=format_utc_datetime(job.created_at),
+                    updated_at=format_utc_datetime(job.updated_at),
                 )
             )
 
@@ -383,7 +384,7 @@ def retry_project_task(
             progress=0,
             current_step=_ingest_step(retried),
             source_id=retried.id,
-            created_at=retried.created_at,
-            updated_at=retried.updated_at,  # type: ignore[attr-defined]
+            created_at=format_utc_datetime(retried.created_at),
+            updated_at=format_utc_datetime(retried.updated_at),  # type: ignore[attr-defined]
         )
     raise HTTPException(status_code=400, detail="Unsupported task type")

apps/api/app/api/routes/videos.py

@@ -15,6 +15,7 @@ from app.schemas.video_center import (
 )
 from fastapi import APIRouter, Depends, HTTPException, Query, Response
 
+from app.api.routes._helpers import format_utc_datetime
 from packages.application import (
     GetGeneratedVideoUseCase,
     GetVideosByIdsUseCase,
@@ -50,7 +51,7 @@ def _to_video_response(item, storage: OSSStorageService | None = None) -> VideoI
         review_status=item.review_status,
         generation_params=item.generation_params,
         download_url=download_url,
-        generated_at=item.generated_at.isoformat() if hasattr(item, "generated_at") and item.generated_at else "",
+        generated_at=format_utc_datetime(item.generated_at) if hasattr(item, "generated_at") else "",
     )
 
 

apps/api/app/schemas/task_center.py

@@ -1,5 +1,3 @@
-from datetime import datetime
-
 from pydantic import BaseModel, Field
 
 
@@ -17,8 +15,8 @@ class ProjectTaskResponse(BaseModel):
     retry_count: int = 0
     source_id: str = ""
     template_id: str = ""
-    created_at: datetime | None = None
-    updated_at: datetime | None = None
+    created_at: str = ""
+    updated_at: str = ""
 
 
 class ListProjectTasksResponse(BaseModel):
@@ -42,8 +40,8 @@ class UserTaskResponse(BaseModel):
     retryable: bool = False
     retry_count: int = 0
     source_id: str = ""
-    created_at: datetime | None = None
-    updated_at: datetime | None = None
+    created_at: str = ""
+    updated_at: str = ""
 
 
 class ListTasksResponse(BaseModel):