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/announcements/[id]/page.tsx

@@ -5,8 +5,7 @@ import { getTranslations } from "next-intl/server"
 
 import { requirePermission } from "@/shared/lib/auth-guard"
 import { Permissions } from "@/shared/types/permissions"
-import { getAnnouncementById } from "@/modules/announcements/data-access"
-import { getGrades } from "@/modules/school/data-access"
+import { getEditAnnouncementPageData } from "@/modules/announcements/data-access"
 import { AnnouncementForm } from "@/modules/announcements/components/announcement-form"
 
 export const dynamic = "force-dynamic"
@@ -28,10 +27,7 @@ export default async function EditAnnouncementPage({
   const { id } = await params
   const t = await getTranslations("announcements")
 
-  const [announcement, grades] = await Promise.all([
-    getAnnouncementById(id),
-    getGrades(),
-  ])
+  const { announcement, grades } = await getEditAnnouncementPageData(id)
 
   if (!announcement) notFound()
 
@@ -44,7 +40,7 @@ export default async function EditAnnouncementPage({
       <AnnouncementForm
         mode="edit"
         announcement={announcement}
-        grades={grades.map((g) => ({ id: g.id, name: g.name }))}
+        grades={grades}
       />
     </div>
   )