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/dashboard/error.tsx

@@ -1,24 +1,7 @@
 "use client"
 
-import { AlertCircle } from "lucide-react"
-import { useTranslations } from "next-intl"
+import { DashboardErrorFallback } from "@/modules/dashboard/components/dashboard-error-fallback"
 
-import { EmptyState } from "@/shared/components/ui/empty-state"
-
-export default function TeacherDashboardError({ reset }: { error: Error & { digest?: string }; reset: () => void }) {
-  const t = useTranslations("dashboard")
-  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>
-  )
+export default function TeacherDashboardError({ error, reset }: { error: Error & { digest?: string }; reset: () => void }) {
+  return <DashboardErrorFallback error={error} reset={reset} />
 }

src/app/(dashboard)/teacher/dashboard/loading.tsx

@@ -1,38 +1,5 @@
-import { Card, CardContent, CardHeader } from "@/shared/components/ui/card"
-import { Skeleton } from "@/shared/components/ui/skeleton"
+import { DashboardLoadingSkeleton } from "@/modules/dashboard/components/dashboard-loading-skeleton"
 
 export default function TeacherDashboardLoading() {
-  return (
-    <div className="flex h-full flex-col space-y-8 p-8">
-      <div className="space-y-2">
-        <Skeleton className="h-8 w-48" />
-        <Skeleton className="h-4 w-64" />
-      </div>
-
-      <div className="grid gap-4 md:grid-cols-2 lg:grid-cols-4">
-        {Array.from({ length: 4 }).map((_, i) => (
-          <Card key={i}>
-            <CardHeader className="pb-2">
-              <Skeleton className="h-4 w-24" />
-            </CardHeader>
-            <CardContent>
-              <Skeleton className="h-8 w-16" />
-              <Skeleton className="mt-2 h-3 w-28" />
-            </CardContent>
-          </Card>
-        ))}
-      </div>
-
-      <Card>
-        <CardHeader>
-          <Skeleton className="h-5 w-32" />
-        </CardHeader>
-        <CardContent className="space-y-3">
-          {Array.from({ length: 6 }).map((_, i) => (
-            <Skeleton key={i} className="h-12 w-full" />
-          ))}
-        </CardContent>
-      </Card>
-    </div>
-  )
+  return <DashboardLoadingSkeleton />
 }