feat: 从书籍生成教案（粘贴目录 + 上传 md 压缩包）

新增「从书籍生成」流程：用户粘贴教材目录（多行）并上传内含各章
.md 的 ZIP（文件名=目录标题），前端用 JSZip 解压匹配，AI 按章节
体量划分课时，预览/编辑后批量生成，每篇以对应章节正文作为上下文。

服务端
- generate.ts: 新增 POST /lessons-from-book（目录条目→AI 划分课时
  JSON，剥围栏/校验/丢非法行）；扩展 POST / 支持可选 content 上下文，
  无 content 时请求体不变（向后兼容）。

前端
- bookImport.ts: normalizeTitle / parseZip / matchToc / assembleContent。
- booksApi.ts: generateLesson 兼容签名 + divideLessonsFromBook。
- useTeachingBook.ts: 抽出 runGenerationPool，新增 generateLessonsFromBook。
- BookImportDialog.vue 多阶段对话框；UploadDropzone 加 accept/multiple；
  菜单串接「从书籍生成」。

顺带修复 5 个遗留失败测试：import 功能已于 fb0b8d1 删除但测试漏删，
清理孤儿测试；批量生成对齐为单参 generateLesson(topic)。

docs/book-import-spec.md 记录规格。

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

server/routes/generate.test.ts

@@ -160,4 +160,149 @@ describe('generate route', () => {
 
     expect(res.status).toBe(502)
   })
+
+  it('does not add content to the prompt when topic is sent alone', async () => {
+    let sentBody = ''
+    globalThis.fetch = mock(async (_url: unknown, init: { body?: string } = {}) => {
+      sentBody = init.body ?? ''
+      return new Response(
+        JSON.stringify({ choices: [{ message: { content: '# x 教学设计' } }] }),
+        { status: 200 },
+      )
+    }) as unknown as typeof fetch
+
+    const app = new Hono().route('/api/generate', createGenerateRouter('test-key'))
+    await app.request('/api/generate', {
+      method: 'POST',
+      headers: { 'Content-Type': 'application/json' },
+      body: JSON.stringify({ topic: 'CSS 弹性布局' }),
+    })
+
+    expect(sentBody).not.toContain('作为编写依据')
+    expect(sentBody).toContain('请围绕主题')
+    expect(sentBody).toContain('生成一份教案。')
+  })
+
+  it('injects chapter content into the prompt when content is provided', async () => {
+    let sentBody = ''
+    globalThis.fetch = mock(async (_url: unknown, init: { body?: string } = {}) => {
+      sentBody = init.body ?? ''
+      return new Response(
+        JSON.stringify({ choices: [{ message: { content: '# x 教学设计' } }] }),
+        { status: 200 },
+      )
+    }) as unknown as typeof fetch
+
+    const app = new Hono().route('/api/generate', createGenerateRouter('test-key'))
+    const res = await app.request('/api/generate', {
+      method: 'POST',
+      headers: { 'Content-Type': 'application/json' },
+      body: JSON.stringify({ topic: 'CSS 弹性布局', content: '弹性盒模型的正文内容片段' }),
+    })
+
+    expect(res.status).toBe(200)
+    expect(sentBody).toContain('作为编写依据')
+    expect(sentBody).toContain('弹性盒模型的正文内容片段')
+  })
+
+  it('returns 400 when entries are missing on lessons-from-book', async () => {
+    const app = new Hono().route('/api/generate', createGenerateRouter('test-key'))
+
+    const res = await app.request('/api/generate/lessons-from-book', {
+      method: 'POST',
+      headers: { 'Content-Type': 'application/json' },
+      body: JSON.stringify({}),
+    })
+
+    expect(res.status).toBe(400)
+  })
+
+  it('parses lessons with sourceIndexes from lessons-from-book', async () => {
+    globalThis.fetch = mock(async () =>
+      new Response(
+        JSON.stringify({
+          choices: [
+            {
+              message: {
+                content:
+                  '{"lessons":[{"title":"C# 入门——搭建环境","sourceIndexes":[0]},{"title":"变量与类型","sourceIndexes":[1,2]}]}',
+              },
+            },
+          ],
+        }),
+        { status: 200 },
+      ),
+    ) as unknown as typeof fetch
+
+    const app = new Hono().route('/api/generate', createGenerateRouter('test-key'))
+    const res = await app.request('/api/generate/lessons-from-book', {
+      method: 'POST',
+      headers: { 'Content-Type': 'application/json' },
+      body: JSON.stringify({
+        entries: [
+          { index: 0, title: '第1章 C# 入门', charCount: 5000 },
+          { index: 1, title: '第2章 变量', charCount: 3000 },
+          { index: 2, title: '第3章 类型', charCount: 2000 },
+        ],
+      }),
+    })
+
+    expect(res.status).toBe(200)
+    const body = (await res.json()) as {
+      lessons: { title: string; sourceIndexes: number[] }[]
+    }
+    expect(body.lessons).toEqual([
+      { title: 'C# 入门——搭建环境', sourceIndexes: [0] },
+      { title: '变量与类型', sourceIndexes: [1, 2] },
+    ])
+  })
+
+  it('strips code fences and drops out-of-range sourceIndexes on lessons-from-book', async () => {
+    globalThis.fetch = mock(async () =>
+      new Response(
+        JSON.stringify({
+          choices: [
+            {
+              message: {
+                content:
+                  '```json\n{"lessons":[{"title":"课时一","sourceIndexes":[0,9]}]}\n```',
+              },
+            },
+          ],
+        }),
+        { status: 200 },
+      ),
+    ) as unknown as typeof fetch
+
+    const app = new Hono().route('/api/generate', createGenerateRouter('test-key'))
+    const res = await app.request('/api/generate/lessons-from-book', {
+      method: 'POST',
+      headers: { 'Content-Type': 'application/json' },
+      body: JSON.stringify({ entries: [{ index: 0, title: '第1章', charCount: 100 }] }),
+    })
+
+    expect(res.status).toBe(200)
+    const body = (await res.json()) as {
+      lessons: { title: string; sourceIndexes: number[] }[]
+    }
+    expect(body.lessons).toEqual([{ title: '课时一', sourceIndexes: [0] }])
+  })
+
+  it('returns 502 when lessons-from-book JSON is malformed', async () => {
+    globalThis.fetch = mock(async () =>
+      new Response(
+        JSON.stringify({ choices: [{ message: { content: '这不是 JSON' } }] }),
+        { status: 200 },
+      ),
+    ) as unknown as typeof fetch
+
+    const app = new Hono().route('/api/generate', createGenerateRouter('test-key'))
+    const res = await app.request('/api/generate/lessons-from-book', {
+      method: 'POST',
+      headers: { 'Content-Type': 'application/json' },
+      body: JSON.stringify({ entries: [{ index: 0, title: '第1章', charCount: 100 }] }),
+    })
+
+    expect(res.status).toBe(502)
+  })
 })