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)/admin/lesson-plans/[planId]/view/error.tsx

@@ -0,0 +1,20 @@
+"use client"
+
+import { useTranslations } from "next-intl"
+import { BookOpen } from "lucide-react"
+import { EmptyState } from "@/shared/components/ui/empty-state"
+
+export default function AdminLessonPlanViewError() {
+  const t = useTranslations("lessonPreparation")
+  return (
+    <div className="p-8">
+      <EmptyState
+        icon={BookOpen}
+        title={t("error.loadFailed")}
+        description={t("error.loadFailedDesc")}
+        action={{ label: t("error.retry"), onClick: () => window.location.reload() }}
+        className="border-none shadow-none"
+      />
+    </div>
+  )
+}