feat: 接入分镜单集重生成接口

接入后端正式单集 Storyboard Shot 重生成能力，补齐校验回执、旧 Shot 缓存失效与页面刷新逻辑。

tests/features/workflows/pages.test.ts

@@ -15,6 +15,7 @@ import ShotTools from '@/features/storyboard/components/ShotTools.vue'
 import {
     designedShot,
     directionsResult,
+    episodeShots,
     storyboardCheckpoint,
     visualStatesResult
 } from '@/features/storyboard/testing/fixtures'
@@ -141,7 +142,7 @@ afterEach(() => {
     wrapper = undefined
     document.body.innerHTML = ''
     vi.unstubAllGlobals()
-    Object.assign(getStoryboardSession(fixture.id), { receipt: null, prompts: {} })
+    Object.assign(getStoryboardSession(fixture.id), { receipt: null, prompts: {}, regeneratedEpisodes: {} })
     getImageSession(fixture.id).receipt = null
     getImageSession(fixture.id).promptReceipt = null
     Object.assign(getOperation(fixture.id), { pending: false, label: '', error: '', notice: '' })
@@ -1190,6 +1191,46 @@ describe('工作台页面交互', () => {
         expect(drawerPanel().text()).toContain('缺少主体状态')
     })
 
+    it('重生成当前集镜头后刷新正式设计，并用接口回执替换过期 Breakdown 文本', async () => {
+        const regenerated = episodeShots()
+        regenerated.beatShots[0]!.shots[0]!.title = '重生成后的开场镜头'
+        regenerated.beatShots[0]!.shots[0]!.description = '新的镜头正文'
+        const fetcher = vi.fn<typeof fetch>().mockImplementation(async (url, init) => {
+            if (init?.method === 'POST')
+                return jsonResponse({
+                    projectId: fixture.id,
+                    episodeNo: 1,
+                    episodeShot: regenerated,
+                    storyboardShotSummary: {
+                        episodeCount: 1,
+                        beatCount: 2,
+                        shotCount: 2,
+                        totalDurationSeconds: 10,
+                        subjectRefCount: 2,
+                        subjectBindingCount: 2,
+                        bindingCoverage: 1
+                    },
+                    storyboardShotValidation: { valid: true, issues: [] }
+                })
+            return jsonResponse(
+                String(url).includes('storyboard-directions')
+                    ? directionsResult(fixture.id, 1, false)
+                    : visualStatesResult(fixture.id)
+            )
+        })
+        vi.stubGlobal('fetch', fetcher)
+        await mountStoryboard()
+        await confirmGeneration('重生成第 1 集镜头')
+        const post = fetcher.mock.calls.find(([, init]) => init?.method === 'POST')!
+        expect(post[0]).toBe('/api/projects/page-test-project/storyboard-shots/regenerate')
+        expect(JSON.parse(post[1]!.body as string)).toEqual({ episodeNo: 1 })
+        expect(wrapper!.text()).toContain('重生成后的开场镜头')
+        expect(wrapper!.text()).toContain('新的镜头正文')
+        expect(drawerPanel().text()).toContain('本集新镜头已保存')
+        expect(drawerPanel().text()).toContain('2 个镜头')
+        expect(fetcher.mock.calls.filter(([, init]) => !init?.method || init.method === 'GET')).toHaveLength(4)
+    })
+
     it('批量 200 部分失败不显示全成功，默认补齐与显式覆盖参数独立', async () => {
         const fetcher = vi.fn<typeof fetch>().mockImplementation(async (url, init) => {
             if (init?.method === 'POST')