feat(脚本): 按流程文档重写脚本阶段(自动提取人物/场景 + 标签胶囊改写 + 基础资产按标签 seed)

后端:
- 出稿后新增轻量提取调用,从脚本抽取人物/场景标签及每个标签的建议生图提示词,
  写入 project.metadata(cast/scenes/cast_prompts/scene_prompts)
- 提取调用接入计费闭环(reserve→charge/release,记为 script_optimization);
  best-effort:无模型/预扣失败/调用失败/解析失败都吞掉返回空,绝不阻断出稿
- generate_base_asset 增加 label,落 group.metadata,把生成结果归回脚本标签卡

前端:
- 设定卡风格补齐到 5 个(真实测评/痛点种草/小红书种草/开箱测评/对比展示)
- 标签改为待确认胶囊流:增删不立即落库,排进队列在输入框上方显示可撤销胶囊,
  点发送才整体重写;待删划线、待加虚线
- 基础资产人物/场景按提取标签逐个 seed 卡,显示 AI 提示词、可改后生成

测试:新增提取+计费+release+label 共 4 个用例,全套 24 个通过(sqlite test 设置)

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

core/frontend/src/App.tsx

@@ -683,7 +683,7 @@ export function App() {
         }
         onAdoptVideoVersion={(segmentId, versionId) => action(() => api.adoptVideoVersion(pipelineProject.id, { video_segment_id: segmentId, version_id: versionId }), "已采用该版本")}
         onGenerateVoiceover={(payload) => action(() => api.generateVoiceover(pipelineProject.id, payload), "配音已生成")}
-        onGenerateBaseAsset={(kind, prompt) => action(() => api.generateBaseAsset(pipelineProject.id, { kind, prompt }), "基础资产已生成")}
+        onGenerateBaseAsset={(kind, prompt, label) => action(() => api.generateBaseAsset(pipelineProject.id, { kind, prompt, label }), "基础资产已生成")}
         onGenerateStoryboard={(prompt) =>
           action(async () => {
             // 异步故事板:提交(秒回)后轮询;后端在后台线程逐帧生成,poll 永远秒回,故每轮间隔等待