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)/teacher/grades/page.tsx

@@ -3,7 +3,7 @@ import Link from "next/link"
 import { PlusCircle, BarChart3, ClipboardList } from "lucide-react"
 import { Button } from "@/shared/components/ui/button"
 import { EmptyState } from "@/shared/components/ui/empty-state"
-import { ListPagination, computePagination, paginate } from "@/shared/components/ui/list-pagination"
+import { ListPagination, computePagination } from "@/shared/components/ui/list-pagination"
 import { requirePermission } from "@/shared/lib/auth-guard"
 import { Permissions } from "@/shared/types/permissions"
 import { getParam, type SearchParams } from "@/shared/lib/search-params"
@@ -43,7 +43,11 @@ export default async function TeacherGradesPage({
   const type = getParam(sp, "type")
   const semester = getParam(sp, "semester")
 
-  const [classes, allSubjects, records] = await Promise.all([
+  // P3 修复：使用 DB 层分页，移除重复计算
+  const { page } = computePagination(sp, PAGE_SIZE)
+  const offset = (page - 1) * PAGE_SIZE
+
+  const [classes, allSubjects, result] = await Promise.all([
     getTeacherClasses(),
     getSubjectOptions(),
     getGradeRecords({
@@ -53,18 +57,19 @@ export default async function TeacherGradesPage({
       subjectId: subjectId && subjectId !== "all" ? subjectId : undefined,
       type: type && type !== "all" ? parseGradeType(type) : undefined,
       semester: semester && semester !== "all" ? parseSemester(semester) : undefined,
+      limit: PAGE_SIZE,
+      offset,
     }),
   ])
 
   const classOptions = classes.map((c) => ({ id: c.id, name: c.name }))
   const subjectOptions = allSubjects.map((s) => ({ id: s.id, name: s.name }))
 
-  // 分页计算
-  const { page } = computePagination(sp, PAGE_SIZE)
-  const total = records.length
+  // 使用 DB 返回的 total 和 totalPages，移除重复计算
+  const total = result.total
   const totalPages = Math.max(1, Math.ceil(total / PAGE_SIZE))
   const currentPage = Math.min(page, totalPages)
-  const pagedRecords = paginate(records, currentPage, PAGE_SIZE)
+  const pagedRecords = result.records
   const hasFilters = Boolean(classId || subjectId || type || semester)
 
   return (
@@ -103,7 +108,7 @@ export default async function TeacherGradesPage({
 
       <GradeQueryFilters classes={classOptions} subjects={subjectOptions} />
 
-      {records.length === 0 && !hasFilters ? (
+      {total === 0 && !hasFilters ? (
         <EmptyState
           title="暂无成绩记录"
           description="开始为您的班级录入成绩。"