refactor: Replace Webpack with Vite (#53)

src/pages/calendar/CalendarMain.tsx

@@ -0,0 +1,10 @@
+import React from 'react';
+import ExtensionRoot from '@views/components/common/ExtensionRoot/ExtensionRoot';
+
+export default function CalendarMain() {
+    return (
+        <ExtensionRoot>
+            <div>Calendar Placeholder</div>
+        </ExtensionRoot>
+    );
+}