feat(app): add lesson-plans, practice, and grade dashboard routes

- Add admin/lesson-plans, parent/lesson-plans, student/lesson-plans routes

- Add student/practice and teacher/practice routes for adaptive practice

- Add management/grade/dashboard and management/grade/practice routes

- Add teacher/lesson-plans error and loading boundaries

- Update existing admin, parent, student, teacher pages with new features

- Update globals.css and proxy middleware

src/app/(dashboard)/management/grade/practice/loading.tsx

@@ -0,0 +1,16 @@
+import { Skeleton } from "@/shared/components/ui/skeleton"
+
+export default function Loading() {
+  return (
+    <div className="flex h-full flex-col space-y-8 p-8">
+      <Skeleton className="h-10 w-48" />
+      <Skeleton className="h-20 w-full" />
+      <div className="grid gap-3 sm:grid-cols-2 lg:grid-cols-5">
+        {Array.from({ length: 5 }).map((_, i) => (
+          <Skeleton key={i} className="h-[100px]" />
+        ))}
+      </div>
+      <Skeleton className="h-[300px] w-full" />
+    </div>
+  )
+}