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/page.tsx

@@ -3,5 +3,5 @@ import { redirect } from "next/navigation"
 export const dynamic = "force-dynamic"
 
 export default function AdminSchoolPage(): never {
-  redirect("/admin/school/classes")
+  redirect("/admin/school/schools")
 }