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)/student/error-book/page.tsx

@@ -0,0 +1,127 @@
+import type { JSX } from "react"
+import { Suspense } from "react"
+
+import { requirePermission } from "@/shared/lib/auth-guard"
+import { Permissions } from "@/shared/types/permissions"
+import { getParam, type SearchParams } from "@/shared/lib/search-params"
+import { Skeleton } from "@/shared/components/ui/skeleton"
+
+import { getErrorBookItems, getErrorBookStats } from "@/modules/error-book/data-access"
+import { ErrorBookStatsCards } from "@/modules/error-book/components/error-book-stats-cards"
+import { ErrorBookFilters } from "@/modules/error-book/components/error-book-filters"
+import { ErrorBookList } from "@/modules/error-book/components/error-book-list"
+import { AddErrorBookDialog } from "@/modules/error-book/components/add-error-book-dialog"
+import type { ErrorBookStatusValue, ErrorBookSourceTypeValue } from "@/modules/error-book/types"
+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"
+
+const VALID_STATUS = new Set(["new", "learning", "mastered", "archived"])
+const VALID_SOURCE = new Set(["exam", "homework", "manual"])
+
+function parseStatus(v?: string): ErrorBookStatusValue | undefined {
+  return v && VALID_STATUS.has(v) ? (v as ErrorBookStatusValue) : undefined
+}
+
+function parseSource(v?: string): ErrorBookSourceTypeValue | undefined {
+  return v && VALID_SOURCE.has(v) ? (v as ErrorBookSourceTypeValue) : undefined
+}
+
+/**
+ * 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,
+  }
+}
+
+async function ErrorBookResults({ searchParams }: { searchParams: Promise<SearchParams> }): Promise<JSX.Element> {
+  const params = await searchParams
+  const ctx = await requirePermission(Permissions.ERROR_BOOK_READ)
+
+  const q = getParam(params, "q")
+  const status = parseStatus(getParam(params, "status"))
+  const sourceType = parseSource(getParam(params, "source"))
+  const dueOnly = getParam(params, "due") === "due"
+
+  const { data: items } = await getErrorBookItems({
+    studentId: ctx.userId,
+    q: q || undefined,
+    status,
+    sourceType,
+    dueOnly,
+    pageSize: 50,
+  })
+
+  return <ErrorBookList items={items} studentId={ctx.userId} errorItems={items} />
+}
+
+function ErrorBookResultsFallback() {
+  return (
+    <div className="grid gap-3 md:grid-cols-2">
+      {Array.from({ length: 4 }).map((_, idx) => (
+        <Skeleton key={idx} className="h-[180px] w-full rounded-md" />
+      ))}
+    </div>
+  )
+}
+
+export default async function StudentErrorBookPage({
+  searchParams,
+}: {
+  searchParams: Promise<SearchParams>
+}): Promise<JSX.Element> {
+  const ctx = await requirePermission(Permissions.ERROR_BOOK_READ)
+  const stats = await getErrorBookStats(ctx.userId)
+  const aiClientService = createAiClientService()
+
+  return (
+    <AiClientProvider service={aiClientService}>
+      <div className="flex h-full flex-col space-y-8 p-8">
+        <div className="flex flex-col justify-between space-y-4 md:flex-row md:items-center md:space-y-0">
+          <div>
+            <h1 className="text-2xl font-bold tracking-tight">错题本</h1>
+            <p className="text-muted-foreground">
+              自动收录考试与作业中的错题，科学复习，攻克薄弱点。
+            </p>
+          </div>
+          <div className="flex items-center gap-2">
+            <AddErrorBookDialog />
+          </div>
+        </div>
+
+        <ErrorBookStatsCards stats={stats} />
+
+        <div className="space-y-4">
+          <Suspense fallback={<div className="h-10 w-full animate-pulse rounded-md bg-muted" />}>
+            <ErrorBookFilters />
+          </Suspense>
+
+          <Suspense fallback={<ErrorBookResultsFallback />}>
+            <ErrorBookResults searchParams={searchParams} />
+          </Suspense>
+        </div>
+      </div>
+    </AiClientProvider>
+  )
+}