feat(textbooks): 教材模块审计重构 — 跨模块解耦 + 权限 + i18n + 错误边界 + 纯函数抽取

P0 修复：
- 解耦跨模块 UI 依赖：knowledge-point-dialogs 不再直接 import questions，
  改为 renderQuestionCreator render prop 由页面注入
- 接入 usePermission Hook 替换 canEdit 硬编码
- 全模块 i18n 改造：新增 en/zh-CN 翻译文件，替换所有硬编码文案
- Server Action 资源归属校验：新增 verifyChapterBelongsToTextbook/
  verifyKnowledgePointBelongsToTextbook，在 reorder/update/delete/create 中校验

P1 改进：
- 补齐 Error Boundary：4 个 error.tsx + TextbookSectionErrorBoundary 区块包裹
- 抽取纯函数到 utils.ts/graph-layout.ts/constants.ts 并补单测（26 用例全通过）
- 消除重复组件：删除 knowledge-point-panel/create-knowledge-point-dialog
- 修复类型断言：chapter.children! → 守卫式访问
- 图谱 a11y：添加 role/aria-label/aria-pressed
- 统一删除确认：confirm() → AlertDialog
- 数据范围过滤：getTextbooksWithScope 支持学生端按年级过滤

P2 预留：
- TextbookAnalytics 埋点接口 + Provider + Hook

同步 005 架构数据 JSON：补充 getTextbooksWithScope/verify*/ChapterTreeNode 等

src/app/(dashboard)/teacher/textbooks/[id]/error.tsx

@@ -0,0 +1,29 @@
+"use client"
+
+import { AlertCircle } from "lucide-react"
+import { useTranslations } from "next-intl"
+
+import { EmptyState } from "@/shared/components/ui/empty-state"
+
+export default function TeacherTextbookDetailError({
+  reset,
+}: {
+  error: Error & { digest?: string }
+  reset: () => void
+}) {
+  const t = useTranslations("textbooks")
+  return (
+    <div className="flex h-full flex-col items-center justify-center space-y-4 p-8">
+      <EmptyState
+        icon={AlertCircle}
+        title={t("error.loadFailed")}
+        description={t("error.loadFailedDesc")}
+        action={{
+          label: t("error.retry"),
+          onClick: () => reset(),
+        }}
+        className="border-none shadow-none h-auto"
+      />
+    </div>
+  )
+}

src/app/(dashboard)/teacher/textbooks/[id]/page.tsx

@@ -1,12 +1,15 @@
-import type { JSX } from "react"
+import type { JSX, ReactNode } from "react"
 import { notFound } from "next/navigation"
 import { ArrowLeft } from "lucide-react"
 import Link from "next/link"
+import { getTranslations } from "next-intl/server"
 import { Button } from "@/shared/components/ui/button"
 import { Badge } from "@/shared/components/ui/badge"
 import { getTextbookById, getChaptersByTextbookId, getKnowledgePointsByTextbookId } from "@/modules/textbooks/data-access"
-import { TextbookReader } from "@/modules/textbooks/components/textbook-reader"
+import { TextbookReader, type TextbookReaderProps } from "@/modules/textbooks/components/textbook-reader"
 import { TextbookSettingsDialog } from "@/modules/textbooks/components/textbook-settings-dialog"
+import { CreateQuestionDialog } from "@/modules/questions/components/create-question-dialog"
+import type { KnowledgePoint } from "@/modules/textbooks/types"
 
 export const dynamic = "force-dynamic"
 
@@ -16,6 +19,7 @@ export default async function TextbookDetailPage({
   params: Promise<{ id: string }>
 }): Promise<JSX.Element> {
   const { id } = await params
+  const t = await getTranslations("textbooks")
 
   const [textbook, chapters, knowledgePoints] = await Promise.all([
     getTextbookById(id),
@@ -27,6 +31,25 @@ export default async function TextbookDetailPage({
     notFound()
   }
 
+  // P0-1 在页面层注入 questions 模块的 CreateQuestionDialog 实现
+  const renderQuestionCreator: TextbookReaderProps["renderQuestionCreator"] = ({
+    open,
+    onOpenChange,
+    targetKp,
+  }: {
+    open: boolean
+    onOpenChange: (open: boolean) => void
+    targetKp: KnowledgePoint | null
+  }): ReactNode => (
+    <CreateQuestionDialog
+      open={open}
+      onOpenChange={onOpenChange}
+      defaultKnowledgePointIds={targetKp ? [targetKp.id] : []}
+      defaultContent={targetKp ? `Please explain the knowledge point: ${targetKp.name}` : ""}
+      defaultType="text"
+    />
+  )
+
   return (
     <div className="flex flex-col h-[calc(100vh-4rem)] overflow-hidden">
       {/* Header / Nav (Fixed height) */}
@@ -34,7 +57,7 @@ export default async function TextbookDetailPage({
         <Button asChild variant="ghost" size="sm">
           <Link href="/teacher/textbooks">
             <ArrowLeft className="mr-2 h-4 w-4" aria-hidden="true" />
-            返回教材列表
+            {t("reader.back")}
           </Link>
         </Button>
         <div className="flex-1 min-w-0">
@@ -57,7 +80,7 @@ export default async function TextbookDetailPage({
           chapters={chapters}
           knowledgePoints={knowledgePoints}
           textbookId={id}
-          canEdit={true}
+          renderQuestionCreator={renderQuestionCreator}
         />
       </div>
     </div>