feat(ai): 新增 AI 模块并集成至备课/错题集/试卷/改题四大业务场景

- 新增 src/modules/ai 独立模块，遵循三层架构（actions → services → shared/lib/ai）
- 通过 AiClientProvider + useAiClient 实现 React Context 依赖注入，业务组件零直接 import
- 6 个 Server Actions 均调用 requirePermission() 权限校验，返回 ActionState<T>
- withAiTracking 统一埋点，覆盖 chat/similar_question/grading_assist/lesson_content/question_variant/weakness_analysis
- 集成场景：作业批改 AiGradingAssist、错题集 AiErrorBookAnalysis、备课 AiLessonContentGenerator、试卷 AiQuestionVariantGenerator
- 全量 i18n（en/zh-CN ai.json），Error Boundary + Skeleton 边界处理
- 同步架构图 004/005，新增审计报告 ai-module-audit-report.md

src/app/(dashboard)/teacher/lesson-plans/[planId]/edit/page.tsx

@@ -1,12 +1,44 @@
 import type { JSX } from "react"
+import { Suspense } from "react"
 import { notFound } from "next/navigation"
 import { getLessonPlanById } from "@/modules/lesson-preparation/data-access"
 import { LessonPlanEditor } from "@/modules/lesson-preparation/components/lesson-plan-editor"
 import { getTeacherClasses } from "@/modules/classes/data-access"
+import { getTextbookById, getChaptersByTextbookId } from "@/modules/textbooks/data-access"
 import { getAuthContext } from "@/shared/lib/auth-guard"
+import { Skeleton } from "@/shared/components/ui/skeleton"
+import {
+  AiClientProvider,
+  type AiClientService,
+} from "@/modules/ai/context/ai-client-provider"
+import {
+  aiChatAction,
+  suggestSimilarQuestionsAction,
+  suggestGradingAction,
+  generateLessonContentAction,
+  generateQuestionVariantAction,
+  analyzeWeaknessAction,
+} from "@/modules/ai/actions"
 
 export const dynamic = "force-dynamic"
 
+/**
+ * 构建 AI 客户端服务（Server Action 引用集合）
+ *
+ * 通过 React Context 注入，客户端组件不直接 import actions，
+ * 遵循依赖注入模式，便于测试时替换为 mock。
+ */
+function createAiClientService(): AiClientService {
+  return {
+    chat: aiChatAction,
+    suggestSimilarQuestions: suggestSimilarQuestionsAction,
+    suggestGrading: suggestGradingAction,
+    generateLessonContent: generateLessonContentAction,
+    generateQuestionVariant: generateQuestionVariantAction,
+    analyzeWeakness: analyzeWeaknessAction,
+  }
+}
+
 export default async function EditLessonPlanPage({
   params,
 }: {
@@ -23,16 +55,53 @@ export default async function EditLessonPlanPage({
 
   const classes = teacherClasses.map((c) => ({ id: c.id, name: c.name }))
 
+  // 拉取教材/章节标题用于工具栏显示
+  let textbookTitle: string | undefined
+  let chapterTitle: string | undefined
+  if (plan.textbookId) {
+    const textbook = await getTextbookById(plan.textbookId)
+    textbookTitle = textbook?.title
+    if (plan.chapterId) {
+      const chapters = await getChaptersByTextbookId(plan.textbookId)
+      const findChapter = (list: typeof chapters): typeof chapters[number] | undefined => {
+        for (const ch of list) {
+          if (ch.id === plan.chapterId) return ch
+          if (ch.children && ch.children.length > 0) {
+            const found = findChapter(ch.children as typeof chapters)
+            if (found) return found
+          }
+        }
+        return undefined
+      }
+      const chapter = findChapter(chapters)
+      chapterTitle = chapter?.title
+    }
+  }
+
+  const aiClientService = createAiClientService()
+
   return (
-    <div className="h-[calc(100vh-4rem)]">
-      <LessonPlanEditor
-        planId={plan.id}
-        initialTitle={plan.title}
-        initialDoc={plan.content}
-        textbookId={plan.textbookId ?? undefined}
-        chapterId={plan.chapterId ?? undefined}
-        classes={classes}
-      />
-    </div>
+    <AiClientProvider service={aiClientService}>
+      <div className="h-[calc(100vh-4rem)]">
+        <Suspense
+          fallback={
+            <div className="flex h-full items-center justify-center">
+              <Skeleton className="h-[80%] w-[80%]" />
+            </div>
+          }
+        >
+          <LessonPlanEditor
+            planId={plan.id}
+            initialTitle={plan.title}
+            initialDoc={plan.content}
+            textbookId={plan.textbookId ?? undefined}
+            chapterId={plan.chapterId ?? undefined}
+            textbookTitle={textbookTitle}
+            chapterTitle={chapterTitle}
+            classes={classes}
+          />
+        </Suspense>
+      </div>
+    </AiClientProvider>
   )
 }