feat(app): add error/loading boundaries and update dashboard routes

- Add error.tsx and loading.tsx boundaries for admin, parent, student, teacher routes

- Add dashboard-error-fallback and dashboard-loading-skeleton components

- Add student/learning page, parent/leave routes, teacher textbook components

- Update existing app routes across auth, dashboard, and API endpoints

- Update proxy middleware and next-auth type declarations

src/app/(dashboard)/student/learning/assignments/[assignmentId]/page.tsx

@@ -24,7 +24,7 @@ export default async function StudentAssignmentTakePage({
   const status = data.submission?.status
   if (status === "graded" || status === "submitted") {
     return (
-      <div className="h-full flex-1 flex-col space-y-8 p-8 md:flex">
+      <div className="space-y-8">
         <div className="flex flex-col gap-1">
           <h2 className="text-2xl font-bold tracking-tight">{data.assignment.title}</h2>
           <div className="text-sm text-muted-foreground">
@@ -38,7 +38,7 @@ export default async function StudentAssignmentTakePage({
   }
 
   return (
-    <div className="flex h-full flex-col space-y-4 p-6">
+    <div className="space-y-4">
       <div className="flex flex-col gap-1">
         <h2 className="text-2xl font-bold tracking-tight">{data.assignment.title}</h2>
         <div className="text-sm text-muted-foreground">

src/app/(dashboard)/student/learning/assignments/page.tsx

@@ -6,6 +6,7 @@ import { Button } from "@/shared/components/ui/button"
 import { Card, CardContent, CardHeader, CardTitle } from "@/shared/components/ui/card"
 import { StatusBadge } from "@/shared/components/ui/status-badge"
 import { formatDate, cn } from "@/shared/lib/utils"
+import { getParam, type SearchParams } from "@/shared/lib/search-params"
 import { getStudentHomeworkAssignments } from "@/modules/homework/data-access"
 import { getCurrentStudentUser } from "@/modules/users/data-access"
 import { AssignmentFilters } from "@/modules/homework/components/assignment-filters"
@@ -20,13 +21,6 @@ import {
 
 export const dynamic = "force-dynamic"
 
-type SearchParams = { [key: string]: string | string[] | undefined }
-
-const getParam = (params: SearchParams, key: string) => {
-  const v = params[key]
-  return Array.isArray(v) ? v[0] : v
-}
-
 const getActionLabel = (status: StudentHomeworkProgressStatus, t: (key: string) => string): string => {
   switch (status) {
     case "graded":

src/app/(dashboard)/student/learning/courses/loading.tsx

@@ -3,7 +3,7 @@ import { Skeleton } from "@/shared/components/ui/skeleton"
 
 export default function Loading() {
   return (
-    <div className="flex h-full flex-col space-y-8 p-8">
+    <div className="space-y-8">
       <div className="space-y-2">
         <Skeleton className="h-8 w-40" />
         <Skeleton className="h-4 w-52" />

src/app/(dashboard)/student/learning/courses/page.tsx

@@ -5,16 +5,10 @@ import { getCurrentStudentUser } from "@/modules/users/data-access"
 import { StudentCoursesView } from "@/modules/student/components/student-courses-view"
 import { CourseFilters } from "@/modules/student/components/course-filters"
 import { EmptyState } from "@/shared/components/ui/empty-state"
+import { getParam, type SearchParams } from "@/shared/lib/search-params"
 
 export const dynamic = "force-dynamic"
 
-type SearchParams = { [key: string]: string | string[] | undefined }
-
-const getParam = (params: SearchParams, key: string) => {
-  const v = params[key]
-  return Array.isArray(v) ? v[0] : v
-}
-
 export default async function StudentCoursesPage({
   searchParams,
 }: {

src/app/(dashboard)/student/learning/page.tsx

@@ -0,0 +1,93 @@
+import Link from "next/link"
+import { BookOpen, PenTool, Library, ArrowRight } from "lucide-react"
+
+import { getStudentClasses } from "@/modules/classes/data-access"
+import { getStudentHomeworkAssignments } from "@/modules/homework/data-access"
+import { getCurrentStudentUser } from "@/modules/users/data-access"
+import { getTextbooks } from "@/modules/textbooks/data-access"
+import { Card, CardContent, CardHeader, CardTitle } from "@/shared/components/ui/card"
+import { EmptyState } from "@/shared/components/ui/empty-state"
+import { UserX } from "lucide-react"
+
+export const dynamic = "force-dynamic"
+
+export default async function StudentLearningPage() {
+  const student = await getCurrentStudentUser()
+  if (!student) {
+    return (
+      <div className="space-y-8">
+        <EmptyState title="No user found" description="Create a student user to see learning." icon={UserX} />
+      </div>
+    )
+  }
+
+  const [classes, assignments, textbooks] = await Promise.all([
+    getStudentClasses(student.id),
+    getStudentHomeworkAssignments(student.id),
+    getTextbooks(),
+  ])
+
+  const now = new Date()
+  const pendingCount = assignments.filter((a) => a.progressStatus !== "submitted" && a.progressStatus !== "graded").length
+  const dueSoonCount = assignments.filter((a) => {
+    if (a.progressStatus === "submitted" || a.progressStatus === "graded") return false
+    if (!a.dueAt) return false
+    const due = new Date(a.dueAt)
+    const in7Days = new Date(now)
+    in7Days.setDate(in7Days.getDate() + 7)
+    return due >= now && due <= in7Days
+  }).length
+
+  const cards = [
+    {
+      title: "Courses",
+      description: "Your enrolled classes.",
+      icon: BookOpen,
+      href: "/student/learning/courses",
+      stat: `${classes.length} enrolled`,
+    },
+    {
+      title: "Assignments",
+      description: "Homework and practice.",
+      icon: PenTool,
+      href: "/student/learning/assignments",
+      stat: `${pendingCount} pending${dueSoonCount > 0 ? ` · ${dueSoonCount} due soon` : ""}`,
+    },
+    {
+      title: "Textbooks",
+      description: "Browse course materials.",
+      icon: Library,
+      href: "/student/learning/textbooks",
+      stat: `${textbooks.length} available`,
+    },
+  ]
+
+  return (
+    <div className="space-y-8">
+      <div>
+        <h2 className="text-2xl font-bold tracking-tight">My Learning</h2>
+        <p className="text-muted-foreground">Your learning hub: courses, assignments, and textbooks.</p>
+      </div>
+
+      <div className="grid gap-6 md:grid-cols-2 lg:grid-cols-3">
+        {cards.map((c) => (
+          <Link key={c.href} href={c.href}>
+            <Card className="h-full transition-all hover:shadow-md hover:border-primary/50">
+              <CardHeader className="flex flex-row items-center justify-between space-y-0 pb-2">
+                <CardTitle className="text-base font-medium">{c.title}</CardTitle>
+                <c.icon className="h-5 w-5 text-muted-foreground" />
+              </CardHeader>
+              <CardContent className="space-y-2">
+                <p className="text-sm text-muted-foreground">{c.description}</p>
+                <div className="flex items-center justify-between">
+                  <span className="text-sm font-medium">{c.stat}</span>
+                  <ArrowRight className="h-4 w-4 text-muted-foreground" />
+                </div>
+              </CardContent>
+            </Card>
+          </Link>
+        ))}
+      </div>
+    </div>
+  )
+}

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

@@ -3,8 +3,9 @@ import { getTranslations } from "next-intl/server"
 
 import { BookOpen } from "lucide-react"
 
-import { getTextbookById, getChaptersByTextbookId, getKnowledgePointsByTextbookId } from "@/modules/textbooks/data-access"
+import { getTextbookById, getChaptersByTextbookId } from "@/modules/textbooks/data-access"
 import { TextbookReader } from "@/modules/textbooks/components/textbook-reader"
+import { getSubjectLabelKey, getGradeLabelKey } from "@/modules/textbooks/constants"
 import { Badge } from "@/shared/components/ui/badge"
 import { EmptyState } from "@/shared/components/ui/empty-state"
 import { getCurrentStudentUser } from "@/modules/users/data-access"
@@ -23,10 +24,9 @@ export default async function StudentTextbookDetailPage({
 
   const { id } = await params
 
-  const [textbook, chapters, knowledgePoints] = await Promise.all([
+  const [textbook, chapters] = await Promise.all([
     getTextbookById(id),
     getChaptersByTextbookId(id),
-    getKnowledgePointsByTextbookId(id)
   ])
 
   if (!textbook) notFound()
@@ -45,9 +45,9 @@ export default async function StudentTextbookDetailPage({
           <h1 className="text-lg font-bold tracking-tight truncate">{textbook.title}</h1>
           <div className="flex items-center gap-2 text-sm text-muted-foreground">
              <span className="hidden sm:inline-block w-px h-4 bg-border" aria-hidden="true" />
-             <Badge variant="outline" className="font-normal text-xs">{textbook.subject}</Badge>
+             <Badge variant="outline" className="font-normal text-xs">{t(`subject.${getSubjectLabelKey(textbook.subject)}`)}</Badge>
              {textbook.grade && (
-               <Badge variant="secondary" className="font-normal text-xs">{textbook.grade}</Badge>
+               <Badge variant="secondary" className="font-normal text-xs">{t(`grade.${getGradeLabelKey(textbook.grade)}`)}</Badge>
              )}
           </div>
         </div>
@@ -66,7 +66,7 @@ export default async function StudentTextbookDetailPage({
         ) : (
           <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} />
+            <TextbookReader key={id} chapters={chapters} textbookId={id} />
           </div>
         )}
       </div>

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

@@ -7,16 +7,10 @@ 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"
+import { getParam, type SearchParams } from "@/shared/lib/search-params"
 
 export const dynamic = "force-dynamic"
 
-type SearchParams = { [key: string]: string | string[] | undefined }
-
-const getParam = (params: SearchParams, key: string): string | undefined => {
-  const v = params[key]
-  return Array.isArray(v) ? v[0] : v
-}
-
 export default async function StudentTextbooksPage({
   searchParams,
 }: {