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)/student/learning/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 StudentTextbookDetailError({
+  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)/student/learning/textbooks/[id]/page.tsx

@@ -1,4 +1,5 @@
 import { notFound } from "next/navigation"
+import { getTranslations } from "next-intl/server"
 
 import { BookOpen } from "lucide-react"
 
@@ -7,6 +8,7 @@ import { TextbookReader } from "@/modules/textbooks/components/textbook-reader"
 import { Badge } from "@/shared/components/ui/badge"
 import { EmptyState } from "@/shared/components/ui/empty-state"
 import { getCurrentStudentUser } from "@/modules/users/data-access"
+import { getGradeNameById } from "@/modules/school/data-access"
 
 export const dynamic = "force-dynamic"
 
@@ -15,6 +17,7 @@ export default async function StudentTextbookDetailPage({
 }: {
   params: Promise<{ id: string }>
 }) {
+  const t = await getTranslations("textbooks")
   const student = await getCurrentStudentUser()
   if (!student) return notFound()
 
@@ -28,6 +31,13 @@ export default async function StudentTextbookDetailPage({
 
   if (!textbook) notFound()
 
+  // P1-1 数据范围过滤：校验教材年级与学生年级匹配
+  // student.gradeId 是 grades 表 id，需解析为年级名称后才能与 textbooks.grade 字符串比较
+  const studentGradeName = student.gradeId ? await getGradeNameById(student.gradeId) : null
+  if (studentGradeName && textbook.grade && textbook.grade !== studentGradeName) {
+    notFound()
+  }
+
   return (
     <div className="flex h-[calc(100vh-4rem-3rem)] flex-col overflow-hidden bg-muted/5">
       <div className="flex items-center justify-between border-b bg-background/95 backdrop-blur supports-[backdrop-filter]:bg-background/60 py-3 px-6 shrink-0 z-10">
@@ -48,13 +58,14 @@ export default async function StudentTextbookDetailPage({
           <div className="h-full flex items-center justify-center rounded-lg border border-dashed bg-card">
             <EmptyState
               icon={BookOpen}
-              title="No chapters"
-              description="This textbook has no chapters yet."
+              title={t("reader.noChapters")}
+              description={t("reader.noChaptersDesc")}
               className="border-none shadow-none"
             />
           </div>
         ) : (
           <div className="h-full min-h-0 max-w-[1600px] mx-auto w-full">
+            {/* 学生端不传 renderQuestionCreator，无题目创建权限 */}
             <TextbookReader chapters={chapters} knowledgePoints={knowledgePoints} />
           </div>
         )}

src/app/(dashboard)/student/learning/textbooks/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 StudentTextbooksError({
+  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)/student/learning/textbooks/page.tsx

@@ -1,16 +1,18 @@
 import { BookOpen, UserX } from "lucide-react"
+import { getTranslations } from "next-intl/server"
 
-import { getTextbooks } from "@/modules/textbooks/data-access"
+import { getTextbooksWithScope } from "@/modules/textbooks/data-access"
 import { TextbookCard } from "@/modules/textbooks/components/textbook-card"
 import { TextbookFilters } from "@/modules/textbooks/components/textbook-filters"
 import { getCurrentStudentUser } from "@/modules/users/data-access"
+import { getGradeNameById } from "@/modules/school/data-access"
 import { EmptyState } from "@/shared/components/ui/empty-state"
 
 export const dynamic = "force-dynamic"
 
 type SearchParams = { [key: string]: string | string[] | undefined }
 
-const getParam = (params: SearchParams, key: string) => {
+const getParam = (params: SearchParams, key: string): string | undefined => {
   const v = params[key]
   return Array.isArray(v) ? v[0] : v
 }
@@ -20,28 +22,39 @@ export default async function StudentTextbooksPage({
 }: {
   searchParams: Promise<SearchParams>
 }) {
+  const t = await getTranslations("textbooks")
   const [student, sp] = await Promise.all([getCurrentStudentUser(), searchParams])
 
   if (!student) {
     return (
-      <div className="h-full flex-1 flex-col space-y-8 p-8 md:flex">
-        <EmptyState title="No user found" description="Create a student user to see textbooks." icon={UserX} />
+      <div className="space-y-8">
+        <EmptyState
+          title={t("student.noUser")}
+          description={t("student.noUserDesc")}
+          icon={UserX}
+        />
       </div>
     )
   }
 
-  const q = getParam(sp, "q") || undefined
-  const subject = getParam(sp, "subject") || undefined
-  const grade = getParam(sp, "grade") || undefined
+  const q = getParam(sp, "q")
+  const subject = getParam(sp, "subject")
+  const grade = getParam(sp, "grade")
 
-  const textbooks = await getTextbooks(q, subject, grade)
+  // P1-1 数据范围过滤：学生端强制按学生所在年级过滤
+  // student.gradeId 是 grades 表 id，需通过 getGradeNameById 解析为年级名称（如 "Grade 7"），
+  // 才能与 textbooks.grade 字符串字段匹配
+  const studentGradeName = student.gradeId ? await getGradeNameById(student.gradeId) : null
+  const textbooks = await getTextbooksWithScope(q, subject, grade, {
+    grade: studentGradeName ?? undefined,
+  })
   const hasFilters = Boolean(q || (subject && subject !== "all") || (grade && grade !== "all"))
 
   return (
-    <div className="h-full flex-1 flex-col space-y-8 p-8 md:flex">
+    <div className="space-y-8">
       <div>
-        <h2 className="text-2xl font-bold tracking-tight">Textbooks</h2>
-        <p className="text-muted-foreground">Browse your course textbooks.</p>
+        <h2 className="text-2xl font-bold tracking-tight">{t("student.list.title")}</h2>
+        <p className="text-muted-foreground">{t("student.list.subtitle")}</p>
       </div>
 
       <TextbookFilters />
@@ -49,19 +62,31 @@ export default async function StudentTextbooksPage({
       {textbooks.length === 0 ? (
         <EmptyState
           icon={BookOpen}
-          title={hasFilters ? "No textbooks match your filters" : "No textbooks yet"}
-          description={hasFilters ? "Try clearing filters or adjusting keywords." : "No textbooks are available right now."}
-          action={hasFilters ? { label: "Clear filters", href: "/student/learning/textbooks" } : undefined}
+          title={hasFilters ? t("student.list.empty.withFilters") : t("student.list.empty.withoutFilters")}
+          description={
+            hasFilters
+              ? t("student.list.empty.withFiltersDesc")
+              : t("student.list.empty.withoutFiltersDesc")
+          }
+          action={
+            hasFilters
+              ? { label: t("list.clearFilters"), href: "/student/learning/textbooks" }
+              : undefined
+          }
           className="bg-card"
         />
       ) : (
         <div className="grid grid-cols-1 gap-6 sm:grid-cols-2 lg:grid-cols-3 xl:grid-cols-4">
           {textbooks.map((textbook) => (
-            <TextbookCard key={textbook.id} textbook={textbook} hrefBase="/student/learning/textbooks" hideActions />
+            <TextbookCard
+              key={textbook.id}
+              textbook={textbook}
+              hrefBase="/student/learning/textbooks"
+              hideActions
+            />
           ))}
         </div>
       )}
     </div>
   )
 }
-