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/diagnostic/student/[studentId]/page.tsx

@@ -8,7 +8,9 @@ import {
   getKnowledgePointStats,
 } from "@/modules/diagnostic/data-access"
 import { getDiagnosticReports } from "@/modules/diagnostic/data-access-reports"
+import { getStudentActiveClassId } from "@/modules/classes/data-access"
 import { StudentDiagnosticView } from "@/modules/diagnostic/components/student-diagnostic-view"
+import { WidgetBoundary } from "@/modules/grades/components/widget-boundary"
 import type { MasteryRadarPoint } from "@/modules/diagnostic/types"
 
 export const dynamic = "force-dynamic"
@@ -29,11 +31,26 @@ export default async function StudentDiagnosticPage({
     notFound()
   }
 
-  const [summary, reports, classStats] = await Promise.all([
+  // v4-P1-2: class_taught scope 校验师生关系
+  // 教师只能查看自己所教班级的学生诊断
+  if (ctx.dataScope.type === "class_taught") {
+    const studentClassId = await getStudentActiveClassId(studentId)
+    if (!studentClassId || !ctx.dataScope.classIds.includes(studentClassId)) {
+      notFound()
+    }
+  }
+
+  // 先查询学生所属班级，再用 classId 调用 getKnowledgePointStats
+  // 否则无参调用会导致 studentIds=[] 直接返回空数组，班级平均对比功能失效
+  const studentClassId = await getStudentActiveClassId(studentId)
+
+  const [summary, reportsResult, classStats] = await Promise.all([
     getStudentMasterySummary(studentId),
-    getDiagnosticReports({ studentId }),
-    getKnowledgePointStats(),
+    // v4-P1-3: 教师视角可查看所有状态报告（含草稿），便于审核
+    getDiagnosticReports({ studentId }, ctx.dataScope),
+    studentClassId ? getKnowledgePointStats(studentClassId) : Promise.resolve([]),
   ])
+  const reports = reportsResult.reports
 
   // 班级平均掌握度（用于雷达图对比）
   let classAverageMastery: MasteryRadarPoint[] | undefined
@@ -56,11 +73,14 @@ export default async function StudentDiagnosticPage({
           Knowledge point mastery analysis and diagnostic reports.
         </p>
       </div>
-      <StudentDiagnosticView
-        summary={summary}
-        reports={reports}
-        classAverageMastery={classAverageMastery}
-      />
+      <WidgetBoundary title="学生学情诊断" skeletonHeight={400}>
+        <StudentDiagnosticView
+          summary={summary}
+          reports={reports}
+          classAverageMastery={classAverageMastery}
+          practiceHrefBase="/teacher/questions"
+        />
+      </WidgetBoundary>
     </div>
   )
 }