feat(home): add AI story expand button and modal

tests/contracts/route-catalog.ts

@@ -163,6 +163,7 @@ const ROUTE_FILES = [
   'src/app/api/user/balance/route.ts',
   'src/app/api/user/costs/details/route.ts',
   'src/app/api/user/costs/route.ts',
+  'src/app/api/user/ai-story-expand/route.ts',
   'src/app/api/user/models/route.ts',
   'src/app/api/user/transactions/route.ts',
 ] as const

tests/contracts/task-type-catalog.ts

@@ -31,6 +31,7 @@ const TASK_TYPE_OWNER_MAP = {
   [TASK_TYPE.SCREENPLAY_CONVERT]: 'tests/unit/worker/screenplay-convert.test.ts',
   [TASK_TYPE.VOICE_ANALYZE]: 'tests/unit/worker/voice-analyze.test.ts',
   [TASK_TYPE.ANALYZE_GLOBAL]: 'tests/unit/worker/analyze-global.test.ts',
+  [TASK_TYPE.AI_STORY_EXPAND]: 'tests/unit/worker/ai-story-expand.test.ts',
   [TASK_TYPE.AI_MODIFY_APPEARANCE]: 'tests/unit/worker/shot-ai-prompt-appearance.test.ts',
   [TASK_TYPE.AI_MODIFY_LOCATION]: 'tests/unit/worker/shot-ai-prompt-location.test.ts',
   [TASK_TYPE.AI_MODIFY_SHOT_PROMPT]: 'tests/unit/worker/shot-ai-prompt-shot.test.ts',

tests/integration/api/contract/llm-observe-routes.test.ts

@@ -171,6 +171,13 @@ const ROUTE_CASES: ReadonlyArray<LLMRouteCase> = [
     expectedTargetType: 'NovelPromotionLocationDesign',
     expectedProjectId: 'project-1',
   },
+  {
+    routeFile: 'src/app/api/user/ai-story-expand/route.ts',
+    body: { prompt: '宫廷复仇女主回京' },
+    expectedTaskType: TASK_TYPE.AI_STORY_EXPAND,
+    expectedTargetType: 'HomeAiStoryExpand',
+    expectedProjectId: 'home-ai-write',
+  },
   {
     routeFile: 'src/app/api/novel-promotion/[projectId]/ai-modify-appearance/route.ts',
     body: {
@@ -336,7 +343,7 @@ describe('api contract - llm observe routes (behavior)', () => {
   })
 
   it('keeps expected coverage size', () => {
-    expect(ROUTE_CASES.length).toBe(22)
+    expect(ROUTE_CASES.length).toBe(23)
   })
 
   for (const routeCase of ROUTE_CASES) {

tests/unit/home/ai-story-expand.test.ts

@@ -0,0 +1,50 @@
+import { describe, expect, it, vi } from 'vitest'
+import { expandHomeStory } from '@/lib/home/ai-story-expand'
+
+vi.mock('@/lib/task/client', () => ({
+  resolveTaskResponse: vi.fn(),
+}))
+
+import { resolveTaskResponse } from '@/lib/task/client'
+
+function buildJsonResponse(body: unknown, status = 200): Response {
+  return new Response(JSON.stringify(body), {
+    status,
+    headers: { 'Content-Type': 'application/json' },
+  })
+}
+
+describe('expandHomeStory', () => {
+  it('posts the prompt to the user ai-story-expand route and returns expanded text', async () => {
+    const apiFetch = vi.fn(async () => buildJsonResponse({ async: true, taskId: 'task-1' }))
+    vi.mocked(resolveTaskResponse).mockResolvedValue({
+      expandedText: '扩写后的故事正文',
+    })
+
+    const result = await expandHomeStory({
+      apiFetch,
+      prompt: '宫廷复仇女主回京',
+    })
+
+    expect(apiFetch).toHaveBeenCalledWith('/api/user/ai-story-expand', {
+      method: 'POST',
+      headers: { 'Content-Type': 'application/json' },
+      body: JSON.stringify({
+        prompt: '宫廷复仇女主回京',
+      }),
+    })
+    expect(result).toEqual({
+      expandedText: '扩写后的故事正文',
+    })
+  })
+
+  it('fails explicitly when the route does not return expandedText', async () => {
+    const apiFetch = vi.fn(async () => buildJsonResponse({ async: true, taskId: 'task-1' }))
+    vi.mocked(resolveTaskResponse).mockResolvedValue({})
+
+    await expect(expandHomeStory({
+      apiFetch,
+      prompt: '宫廷复仇女主回京',
+    })).rejects.toThrow('AI story expand response missing expandedText')
+  })
+})

tests/unit/home/quick-start-textarea.test.ts

@@ -59,6 +59,10 @@ vi.mock('@/lib/home/create-project-launch', () => ({
   createHomeProjectLaunch: vi.fn(),
 }))
 
+vi.mock('@/lib/home/ai-story-expand', () => ({
+  expandHomeStory: vi.fn(),
+}))
+
 describe('resolveTextareaTargetHeight', () => {
   it('keeps the home quick-start input at least three rows tall', () => {
     expect(resolveTextareaTargetHeight({

tests/unit/task/intent.test.ts

@@ -7,6 +7,7 @@ describe('resolveTaskIntent', () => {
     expect(resolveTaskIntent(TASK_TYPE.IMAGE_CHARACTER)).toBe('generate')
     expect(resolveTaskIntent(TASK_TYPE.IMAGE_LOCATION)).toBe('generate')
     expect(resolveTaskIntent(TASK_TYPE.VIDEO_PANEL)).toBe('generate')
+    expect(resolveTaskIntent(TASK_TYPE.AI_STORY_EXPAND)).toBe('generate')
   })
 
   it('maps regenerate and modify task types', () => {

tests/unit/worker/ai-story-expand.test.ts

@@ -0,0 +1,84 @@
+import type { Job } from 'bullmq'
+import { beforeEach, describe, expect, it, vi } from 'vitest'
+import { TASK_TYPE, type TaskJobData } from '@/lib/task/types'
+
+const aiRuntimeMock = vi.hoisted(() => ({
+  executeAiTextStep: vi.fn(async () => ({
+    text: '扩写后的完整故事内容',
+    reasoning: '',
+  })),
+}))
+
+const workerMock = vi.hoisted(() => ({
+  reportTaskProgress: vi.fn(async () => undefined),
+  assertTaskActive: vi.fn(async () => undefined),
+}))
+
+vi.mock('@/lib/ai-runtime', () => aiRuntimeMock)
+vi.mock('@/lib/llm-observe/internal-stream-context', () => ({
+  withInternalLLMStreamCallbacks: vi.fn(async (_callbacks: unknown, fn: () => Promise<unknown>) => await fn()),
+}))
+vi.mock('@/lib/prompt-i18n', () => ({
+  PROMPT_IDS: { NP_AI_STORY_EXPAND: 'np_ai_story_expand' },
+  buildPrompt: vi.fn(() => 'story-expand-prompt'),
+}))
+vi.mock('@/lib/workers/shared', () => ({ reportTaskProgress: workerMock.reportTaskProgress }))
+vi.mock('@/lib/workers/utils', () => ({ assertTaskActive: workerMock.assertTaskActive }))
+vi.mock('@/lib/workers/handlers/llm-stream', () => ({
+  createWorkerLLMStreamContext: vi.fn(() => ({ streamRunId: 'run-1', nextSeqByStepLane: {} })),
+  createWorkerLLMStreamCallbacks: vi.fn(() => ({
+    onStage: vi.fn(),
+    onChunk: vi.fn(),
+    onComplete: vi.fn(),
+    onError: vi.fn(),
+    flush: vi.fn(async () => undefined),
+  })),
+}))
+
+import { handleAiStoryExpandTask } from '@/lib/workers/handlers/ai-story-expand'
+
+function buildJob(payload: Record<string, unknown>): Job<TaskJobData> {
+  return {
+    data: {
+      taskId: 'task-ai-story-expand-1',
+      type: TASK_TYPE.AI_STORY_EXPAND,
+      locale: 'zh',
+      projectId: 'home-ai-write',
+      targetType: 'HomeAiStoryExpand',
+      targetId: 'user-1',
+      payload,
+      userId: 'user-1',
+    },
+  } as unknown as Job<TaskJobData>
+}
+
+describe('worker ai-story-expand behavior', () => {
+  beforeEach(() => {
+    vi.clearAllMocks()
+  })
+
+  it('missing prompt -> explicit error', async () => {
+    const job = buildJob({ prompt: '   ', analysisModel: 'provider::analysis-model' })
+    await expect(handleAiStoryExpandTask(job)).rejects.toThrow('prompt is required')
+  })
+
+  it('missing analysis model -> explicit error', async () => {
+    const job = buildJob({ prompt: '宫廷复仇女主回京' })
+    await expect(handleAiStoryExpandTask(job)).rejects.toThrow('analysisModel is required')
+  })
+
+  it('success path -> returns expanded text without touching episode persistence', async () => {
+    const job = buildJob({ prompt: '宫廷复仇女主回京', analysisModel: 'provider::analysis-model' })
+    const result = await handleAiStoryExpandTask(job)
+
+    expect(result).toEqual({
+      expandedText: '扩写后的完整故事内容',
+    })
+    expect(aiRuntimeMock.executeAiTextStep).toHaveBeenCalledWith(expect.objectContaining({
+      userId: 'user-1',
+      model: 'provider::analysis-model',
+      projectId: 'home-ai-write',
+      action: 'ai_story_expand',
+    }))
+  })
+})