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)/admin/school/grades/insights/page.tsx

@@ -1,4 +1,4 @@
-import Link from "next/link"
+import Link from "next/link"
 import type { Metadata } from "next"
 import type { JSX } from "react"
 import { BarChart3 } from "lucide-react"
@@ -7,13 +7,16 @@ import { requirePermission } from "@/shared/lib/auth-guard"
 import { Permissions } from "@/shared/types/permissions"
 import { getGrades } from "@/modules/school/data-access"
 import { getGradeHomeworkInsights } from "@/modules/classes/data-access"
+import { getSchoolWideGradeSummary } from "@/modules/grades/data-access-analytics"
+import { SchoolWideSummaryCard } from "@/modules/grades/components/school-wide-summary-card"
 import { EmptyState } from "@/shared/components/ui/empty-state"
 import { StatCard } from "@/shared/components/ui/stat-card"
 import { Card, CardContent, CardHeader, CardTitle } from "@/shared/components/ui/card"
 import { Badge } from "@/shared/components/ui/badge"
 import { Button } from "@/shared/components/ui/button"
 import { Table, TableBody, TableCell, TableHead, TableHeader, TableRow } from "@/shared/components/ui/table"
-import { formatDate, formatNumber, getSearchParam, type SearchParams } from "@/shared/lib/utils"
+import { formatDate, formatNumber } from "@/shared/lib/utils"
+import { getParam, type SearchParams } from "@/shared/lib/search-params"
 
 export const metadata: Metadata = {
   title: "年级作业洞察 - Next_Edu",
@@ -27,15 +30,17 @@ export default async function AdminGradeInsightsPage({
 }: {
   searchParams: Promise<SearchParams>
 }): Promise<JSX.Element> {
-  await requirePermission(Permissions.SCHOOL_MANAGE)
+  const ctx = await requirePermission(Permissions.SCHOOL_MANAGE)
   const params = await searchParams
-  const gradeId = getSearchParam(params, "gradeId")
+  const gradeId = getParam(params, "gradeId")
   const selected = gradeId && gradeId !== "all" ? gradeId : ""
 
-  // grades 与 insights 无数据依赖，并行查询
-  const [grades, insights] = await Promise.all([
+  // grades、insights、全校汇总无数据依赖，并行查询
+  const [grades, insights, schoolWideSummary] = await Promise.all([
     getGrades(),
     selected ? getGradeHomeworkInsights({ gradeId: selected, limit: 50 }) : Promise.resolve(null),
+    // v3-P2-9：管理员全校成绩汇总视图
+    getSchoolWideGradeSummary(ctx.dataScope),
   ])
 
   return (
@@ -50,6 +55,11 @@ export default async function AdminGradeInsightsPage({
         </Button>
       </div>
 
+      {/* v3-P2-9: 全校成绩汇总视图 */}
+      {schoolWideSummary.grades.length > 0 && (
+        <SchoolWideSummaryCard summary={schoolWideSummary} />
+      )}
+
       <Card className="shadow-none">
         <CardHeader className="flex flex-row items-center justify-between space-y-0">
           <CardTitle className="text-base">筛选</CardTitle>