feat(video): 视频页「导出全部」— 把项目所有视频片段打包成 zip 下载

- 后端 ProjectViewSet 加 export-clips action:逐段从 TOS 拉取已采用视频片段、内存 zip 打包返回下载
  (单段失败跳过不毁整包;空项目 400);文件名走 RFC5987 UTF-8 编码兼容中文
- 前端视频阶段 queue-bar 在「上传视频」旁加「导出全部」按钮(下载图标 + 导出中/失败态),
  api.exportProjectClips 取 blob → 触发浏览器下载;仅有已完成片段时可点
- 单测 ExportClipsTests:打包全部片段 + 空项目 400

验收:后端单测绿(基线 4 失败零新增);tsc+build 绿;真打包 补水面膜 项目得 950KB zip;无头 0 报错
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

core/backend/apps/projects/views.py

@@ -4,7 +4,7 @@ import uuid
 
 from django.db import transaction
 from django.db.models import Count
-from django.http import JsonResponse, StreamingHttpResponse
+from django.http import HttpResponse, JsonResponse, StreamingHttpResponse
 from rest_framework import status
 from rest_framework.decorators import action
 from rest_framework.parsers import FormParser, MultiPartParser
@@ -154,6 +154,59 @@ class ProjectViewSet(TeamScopedViewSetMixin, ModelViewSet):
             return qs.filter(**{self.team_field: self.get_team()}).order_by("-updated_at")
         return super().get_queryset()
 
+    @action(detail=True, methods=["get"], url_path="export-clips")
+    def export_clips(self, request, pk=None):
+        """导出全部:把该项目所有已采用的视频片段打成一个 zip(逐段从 TOS 拉取,内存打包后下载)。
+        片段短(每段 ~15s),内存打包足够;单段拉取失败跳过不毁整包。"""
+        import io
+        import zipfile
+        from urllib.parse import quote
+
+        import requests
+
+        project = self.get_object()
+        segs = (
+            project.video_segments.filter(adopted_version__isnull=False)
+            .select_related("adopted_version__asset")
+            .prefetch_related("adopted_version__asset__files")
+            .order_by("sort_order")
+        )
+        clips = []
+        for seg in segs:
+            asset = getattr(seg.adopted_version, "asset", None)
+            if asset is None:
+                continue
+            f = asset.files.filter(is_primary=True).first() or asset.files.first()
+            if f and f.object_key:
+                clips.append((seg.sort_order, f))
+        if not clips:
+            return Response({"detail": "该项目还没有可导出的视频片段"}, status=status.HTTP_400_BAD_REQUEST)
+
+        buf = io.BytesIO()
+        storage = TosStorage()
+        packed = 0
+        with zipfile.ZipFile(buf, "w", zipfile.ZIP_STORED) as zf:
+            for order, f in clips:
+                try:
+                    url = storage.presigned_get_url(object_key=f.object_key)
+                    data = requests.get(url, timeout=120).content
+                except Exception:  # noqa: BLE001 — 单段失败跳过,不毁整包
+                    continue
+                ext = ".mp4"
+                if f.content_type and "/" in f.content_type:
+                    sub = f.content_type.rsplit("/", 1)[-1]
+                    ext = "." + ("mov" if sub == "quicktime" else sub if sub in ("mp4", "webm") else "mp4")
+                zf.writestr(f"{order + 1:02d}-镜{order + 1}{ext}", data)
+                packed += 1
+        if packed == 0:
+            return Response({"detail": "视频片段拉取失败,请稍后重试"}, status=status.HTTP_502_BAD_GATEWAY)
+        payload = buf.getvalue()
+        resp = HttpResponse(payload, content_type="application/zip")
+        fname = quote(f"{project.name}-视频素材.zip")
+        resp["Content-Disposition"] = f"attachment; filename=videos.zip; filename*=UTF-8''{fname}"
+        resp["Content-Length"] = str(len(payload))
+        return resp
+
     @action(detail=False, methods=["get"])
     def summary(self, request):
         """项目统计(总数 + 各状态计数),供仪表盘/侧栏徽标——只跑 COUNT,不拉项目对象。"""