fix(video): 视频片段数对齐采用版分镜数,修「删分镜后视频步骤仍显示旧数量」

项目创建固定铺 4 段视频片段,而 _sync_video_segments_to_script 仅在
增删分镜且该脚本 is_adopted 时才收口。用户通常「采用前」就增删分镜,
那些编辑被 is_adopted 闸跳过;adopt_script 自身又不收口 → 视频步骤
一直停在 4 段,与故事板/采用版分镜对不上。

- adopt_script:采用时按这版分镜数收口视频片段
- poll/skip-storyboard:进入视频阶段前再收口一次(安全网)
- retrieve:视频阶段详情加载时自愈历史脏项目(只裁从未生成过的尾段)
- 已生成/生成中的段绝不动;新增 3 个回归测试

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

core/backend/apps/projects/views.py

@@ -140,6 +140,22 @@ class ProjectViewSet(TeamScopedViewSetMixin, ModelViewSet):
         # 列表用轻量序列化(只给列表/仪表盘/侧栏要的字段);详情/写操作用全量 ProjectSerializer
         return ProjectListSerializer if self.action == "list" else ProjectSerializer
 
+    def retrieve(self, request, *args, **kwargs):
+        # 详情加载(=进入流水线页)时自愈视频片段数:历史项目在「采用前增删分镜」未同步,
+        # 或项目创建固定铺的 4 段从未被收口,会让视频步骤的片段数与故事板/采用版分镜对不上。
+        # 按采用版分镜数收口一次(幂等;只裁从未生成过的尾段,生成中/已出片的段绝不动)。
+        # 用轻量查询判定 + 同步,再交给 super 做重 prefetch 序列化(避免重查询跑两遍)。
+        proj = (
+            Project.objects.filter(pk=kwargs.get("pk"), **{self.team_field: self.get_team()})
+            .only("id", "current_stage")
+            .first()
+        )
+        if proj is not None and proj.current_stage == ProjectStage.Stage.VIDEO:
+            adopted_script = proj.script_versions.filter(is_adopted=True).order_by("-created_at").first()
+            if adopted_script is not None:
+                self._sync_video_segments_to_script(proj, adopted_script)
+        return super().retrieve(request, *args, **kwargs)
+
     def get_queryset(self):
         # 列表:轻查询(只 select_related product + 计数注解),不做详情那串 12 个重 prefetch
         # ——原列表把每个项目的 阶段/片段/故事板/时间线/资产文件全拉出,20 个项目实测 ~2s。
@@ -285,6 +301,10 @@ class ProjectViewSet(TeamScopedViewSetMixin, ModelViewSet):
         ScriptVersion.objects.filter(project=project).update(is_adopted=False)
         script.is_adopted = True
         script.save(update_fields=["is_adopted", "updated_at"])
+        # 采用脚本时把视频片段数对齐到这版分镜数:用户常在「采用前」就增删分镜,
+        # 那些编辑因 _sync 的 is_adopted 闸而未同步到 VideoSegment(项目创建时固定铺了 4 段),
+        # 不在此收口的话视频步骤会一直停在 4 段,与故事板/分镜数对不上。已生成的段绝不动。
+        self._sync_video_segments_to_script(project, script)
         stage, _ = ProjectStage.objects.get_or_create(project=project, stage=ProjectStage.Stage.SCRIPT)
         stage.status = ProjectStage.Status.SUCCEEDED
         stage.save(update_fields=["status", "updated_at"])
@@ -631,6 +651,10 @@ class ProjectViewSet(TeamScopedViewSetMixin, ModelViewSet):
             stage, _ = ProjectStage.objects.get_or_create(project=project, stage=ProjectStage.Stage.STORYBOARD)
             stage.status = ProjectStage.Status.SUCCEEDED
             stage.save(update_fields=["status", "updated_at"])
+            # 进入视频阶段前再收口一次视频片段数,确保与采用版分镜数一致(已生成的段不动)
+            adopted_script = project.script_versions.filter(is_adopted=True).order_by("-created_at").first()
+            if adopted_script is not None:
+                self._sync_video_segments_to_script(project, adopted_script)
             project.current_stage = ProjectStage.Stage.VIDEO
             project.status = Project.Status.VIDEOING
             project.save(update_fields=["current_stage", "status", "updated_at"])
@@ -644,6 +668,10 @@ class ProjectViewSet(TeamScopedViewSetMixin, ModelViewSet):
         stage, _ = ProjectStage.objects.get_or_create(project=project, stage=ProjectStage.Stage.STORYBOARD)
         stage.status = ProjectStage.Status.SKIPPED
         stage.save(update_fields=["status", "updated_at"])
+        # 跳过故事板直接进视频时,同样把视频片段数对齐到采用版分镜数(已生成的段不动)
+        adopted_script = project.script_versions.filter(is_adopted=True).order_by("-created_at").first()
+        if adopted_script is not None:
+            self._sync_video_segments_to_script(project, adopted_script)
         project.current_stage = ProjectStage.Stage.VIDEO
         project.status = Project.Status.VIDEOING
         project.save(update_fields=["current_stage", "status", "updated_at"])