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/modules/textbooks/components/textbook-reader.tsx

@@ -1,12 +1,15 @@
 "use client"
 
-import { useMemo, useState, useEffect } from "react"
+import { useMemo, useState, useEffect, type ReactNode } from "react"
 import { useQueryState, parseAsString } from "nuqs"
 import { Tag, List, Share2 } from "lucide-react"
+import { useTranslations } from "next-intl"
 import { toast } from "sonner"
 
 import type { Chapter, KnowledgePoint } from "../types"
 import { updateChapterContentAction } from "../actions"
+import { Permissions } from "@/shared/types/permissions"
+import { usePermission } from "@/shared/hooks/use-permission"
 import { ScrollArea } from "@/shared/components/ui/scroll-area"
 import { Tabs, TabsContent, TabsList, TabsTrigger } from "@/shared/components/ui/tabs"
 import { Badge } from "@/shared/components/ui/badge"
@@ -25,35 +28,46 @@ import { ChapterSidebarList } from "./chapter-sidebar-list"
 import { KnowledgeGraph } from "./knowledge-graph"
 import { KnowledgePointList } from "./knowledge-point-list"
 import { TextbookContentPanel } from "./textbook-content-panel"
-import { KnowledgePointDialogs } from "./knowledge-point-dialogs"
+import {
+  KnowledgePointDialogs,
+  type QuestionCreatorRenderProps,
+} from "./knowledge-point-dialogs"
+import { TextbookSectionErrorBoundary } from "./section-error-boundary"
 import { useTextSelection } from "../hooks/use-text-selection"
 import { useKnowledgePointActions } from "../hooks/use-knowledge-point-actions"
+import { buildChapterIndex } from "../utils"
 
-function buildChapterIndex(chapters: Chapter[]) {
-  const index = new Map<string, Chapter>()
-
-  const walk = (nodes: Chapter[]) => {
-    for (const node of nodes) {
-      index.set(node.id, node)
-      if (node.children && node.children.length > 0) walk(node.children)
-    }
-  }
-
-  walk(chapters)
-  return index
+export interface TextbookReaderProps {
+  chapters: Chapter[]
+  knowledgePoints?: KnowledgePoint[]
+  /**
+   * 是否可编辑。已废弃——改由内部 usePermission() 自动判断。
+   * 保留 prop 仅为向后兼容，传入值会被忽略。
+   * @deprecated 改用权限系统自动判断
+   */
+  canEdit?: boolean
+  textbookId?: string
+  /**
+   * 题目创建器渲染函数（P0-1 解耦）。
+   * 由页面层注入 questions 模块的 CreateQuestionDialog 实现。
+   * 不传则不渲染题目创建入口。
+   */
+  renderQuestionCreator?: (props: QuestionCreatorRenderProps) => ReactNode
 }
 
 export function TextbookReader({
   chapters,
   knowledgePoints = [],
-  canEdit = false,
   textbookId,
-}: {
-  chapters: Chapter[]
-  knowledgePoints?: KnowledgePoint[]
-  canEdit?: boolean
-  textbookId?: string
-}) {
+  renderQuestionCreator,
+}: TextbookReaderProps) {
+  const t = useTranslations("textbooks")
+  const { hasPermission } = usePermission()
+
+  // P0-2 前端权限改由 usePermission 判断，不再接受外部 canEdit 硬编码
+  const canEdit = hasPermission(Permissions.TEXTBOOK_UPDATE)
+  const canCreateQuestion = hasPermission(Permissions.QUESTION_CREATE)
+
   const [chapterId, setChapterId] = useQueryState("chapterId", parseAsString.withDefault(""))
   const [activeTab, setActiveTab] = useState("chapters")
   const [highlightedKpId, setHighlightedKpId] = useState<string | null>(null)
@@ -185,11 +199,11 @@ export function TextbookReader({
             <TabsList className="grid w-full grid-cols-3">
               <TabsTrigger value="chapters" className="gap-2">
                 <List className="h-4 w-4" />
-                章节目录
+                {t("reader.tabs.chapters")}
               </TabsTrigger>
               <TabsTrigger value="knowledge" className="gap-2" disabled={!selectedId}>
                 <Tag className="h-4 w-4" />
-                知识点
+                {t("reader.tabs.knowledge")}
                 {currentChapterKPs.length > 0 && (
                   <Badge variant="secondary" className="ml-1 px-1 py-0 h-5 text-[10px]">
                     {currentChapterKPs.length}
@@ -198,61 +212,80 @@ export function TextbookReader({
               </TabsTrigger>
               <TabsTrigger value="graph" className="gap-2" disabled={!selectedId}>
                 <Share2 className="h-4 w-4" />
-                图谱
+                {t("reader.tabs.graph")}
               </TabsTrigger>
             </TabsList>
           </div>
 
           <TabsContent value="chapters" className="flex-1 min-h-0 mt-0">
-            <ScrollArea className="flex-1 h-full px-2">
-              <div className="space-y-1 pb-4">
-                <ChapterSidebarList
-                  chapters={chapters}
-                  selectedChapterId={selectedId || undefined}
-                  onSelectChapter={handleSelect}
-                  textbookId={textbookId || ""}
-                  canEdit={canEdit}
-                />
-              </div>
-            </ScrollArea>
+            <TextbookSectionErrorBoundary
+              fallbackTitle={t("error.loadFailed")}
+              fallbackDescription={t("error.loadFailedDesc")}
+              retryLabel={t("error.retry")}
+            >
+              <ScrollArea className="flex-1 h-full px-2">
+                <div className="space-y-1 pb-4">
+                  <ChapterSidebarList
+                    chapters={chapters}
+                    selectedChapterId={selectedId || undefined}
+                    onSelectChapter={handleSelect}
+                    textbookId={textbookId || ""}
+                    canEdit={canEdit}
+                  />
+                </div>
+              </ScrollArea>
+            </TextbookSectionErrorBoundary>
           </TabsContent>
 
           <TabsContent value="knowledge" className="flex-1 min-h-0 mt-0">
-            {!selectedId ? (
-              <div className="flex h-full items-center justify-center text-muted-foreground p-4 text-center text-sm">
-                请选择一个章节查看知识点。
-              </div>
-            ) : (
-              <KnowledgePointList
-                knowledgePoints={currentChapterKPs}
-                canEdit={canEdit}
-                highlightedKpId={highlightedKpId}
-                onHighlight={setHighlightedKpId}
-                onEdit={(kp) => {
-                  setEditingKp(kp)
-                  setEditKpDialogOpen(true)
-                }}
-                onDelete={requestDeleteKnowledgePoint}
-                onCreateQuestion={(kp) => {
-                  setTargetKpForQuestion(kp)
-                  setQuestionDialogOpen(true)
-                }}
-              />
-            )}
+            <TextbookSectionErrorBoundary
+              fallbackTitle={t("error.loadFailed")}
+              fallbackDescription={t("error.loadFailedDesc")}
+              retryLabel={t("error.retry")}
+            >
+              {!selectedId ? (
+                <div className="flex h-full items-center justify-center text-muted-foreground p-4 text-center text-sm">
+                  {t("reader.selectChapterKnowledge")}
+                </div>
+              ) : (
+                <KnowledgePointList
+                  knowledgePoints={currentChapterKPs}
+                  canEdit={canEdit}
+                  canCreateQuestion={canCreateQuestion}
+                  highlightedKpId={highlightedKpId}
+                  onHighlight={setHighlightedKpId}
+                  onEdit={(kp) => {
+                    setEditingKp(kp)
+                    setEditKpDialogOpen(true)
+                  }}
+                  onDelete={requestDeleteKnowledgePoint}
+                  onCreateQuestion={(kp) => {
+                    setTargetKpForQuestion(kp)
+                    setQuestionDialogOpen(true)
+                  }}
+                />
+              )}
+            </TextbookSectionErrorBoundary>
           </TabsContent>
 
           <TabsContent value="graph" className="flex-1 min-h-0 mt-0">
-            {!selectedId ? (
-              <div className="flex h-full items-center justify-center text-muted-foreground p-4 text-center text-sm">
-                请选择一个章节查看知识图谱。
-              </div>
-            ) : (
-              <KnowledgeGraph
-                knowledgePoints={currentChapterKPs}
-                selectedId={highlightedKpId}
-                onHighlight={setHighlightedKpId}
-              />
-            )}
+            <TextbookSectionErrorBoundary
+              fallbackTitle={t("error.loadFailed")}
+              fallbackDescription={t("error.loadFailedDesc")}
+              retryLabel={t("error.retry")}
+            >
+              {!selectedId ? (
+                <div className="flex h-full items-center justify-center text-muted-foreground p-4 text-center text-sm">
+                  {t("reader.selectChapterGraph")}
+                </div>
+              ) : (
+                <KnowledgeGraph
+                  knowledgePoints={currentChapterKPs}
+                  selectedId={highlightedKpId}
+                  onHighlight={setHighlightedKpId}
+                />
+              )}
+            </TextbookSectionErrorBoundary>
           </TabsContent>
         </Tabs>
       </div>
@@ -261,14 +294,14 @@ export function TextbookReader({
         <AlertDialog open={deleteConfirmOpen} onOpenChange={setDeleteConfirmOpen}>
           <AlertDialogContent>
             <AlertDialogHeader>
-              <AlertDialogTitle>确认删除</AlertDialogTitle>
-              <AlertDialogDescription>
-                确定要删除这个知识点吗？此操作无法撤销。
-              </AlertDialogDescription>
+              <AlertDialogTitle>{t("dialog.knowledge.deleteTitle")}</AlertDialogTitle>
+              <AlertDialogDescription>{t("dialog.knowledge.deleteDesc")}</AlertDialogDescription>
             </AlertDialogHeader>
             <AlertDialogFooter>
-              <AlertDialogCancel>取消</AlertDialogCancel>
-              <AlertDialogAction onClick={confirmDeleteKnowledgePoint}>删除</AlertDialogAction>
+              <AlertDialogCancel>{t("dialog.knowledge.cancel")}</AlertDialogCancel>
+              <AlertDialogAction onClick={confirmDeleteKnowledgePoint}>
+                {t("dialog.knowledge.delete")}
+              </AlertDialogAction>
             </AlertDialogFooter>
           </AlertDialogContent>
         </AlertDialog>
@@ -287,32 +320,39 @@ export function TextbookReader({
           questionDialogOpen={questionDialogOpen}
           setQuestionDialogOpen={setQuestionDialogOpen}
           targetKpForQuestion={targetKpForQuestion}
+          renderQuestionCreator={canCreateQuestion ? renderQuestionCreator : undefined}
         />
 
-        <TextbookContentPanel
-          selected={selected}
-          isEditing={isEditing}
-          editContent={editContent}
-          setEditContent={setEditContent}
-          canEdit={canEdit}
-          knowledgePoints={currentChapterKPs}
-          highlightedKpId={highlightedKpId}
-          onHighlight={setHighlightedKpId}
-          onSwitchToKnowledgeTab={() => setActiveTab("knowledge")}
-          contentRef={contentRef}
-          onPointerDown={handleContentPointerDown}
-          onContextMenuChange={handleContextMenuChange}
-          selectedText={selectedText}
-          createDialogOpen={createDialogOpen}
-          setCreateDialogOpen={setCreateDialogOpen}
-          isCreating={isCreating}
-          onCreateKnowledgePoint={onCreateKnowledgePoint}
-          startEditing={startEditing}
-          cancelEditing={() => setIsEditing(false)}
-          saveContent={handleSaveContent}
-          isSaving={isSaving}
-          processedContent={processedContent}
-        />
+        <TextbookSectionErrorBoundary
+          fallbackTitle={t("error.loadFailed")}
+          fallbackDescription={t("error.loadFailedDesc")}
+          retryLabel={t("error.retry")}
+        >
+          <TextbookContentPanel
+            selected={selected}
+            isEditing={isEditing}
+            editContent={editContent}
+            setEditContent={setEditContent}
+            canEdit={canEdit}
+            knowledgePoints={currentChapterKPs}
+            highlightedKpId={highlightedKpId}
+            onHighlight={setHighlightedKpId}
+            onSwitchToKnowledgeTab={() => setActiveTab("knowledge")}
+            contentRef={contentRef}
+            onPointerDown={handleContentPointerDown}
+            onContextMenuChange={handleContextMenuChange}
+            selectedText={selectedText}
+            createDialogOpen={createDialogOpen}
+            setCreateDialogOpen={setCreateDialogOpen}
+            isCreating={isCreating}
+            onCreateKnowledgePoint={onCreateKnowledgePoint}
+            startEditing={startEditing}
+            cancelEditing={() => setIsEditing(false)}
+            saveContent={handleSaveContent}
+            isSaving={isSaving}
+            processedContent={processedContent}
+          />
+        </TextbookSectionErrorBoundary>
       </div>
     </div>
   )