fix: 잔존 서비스 워커 제거

Author: ff1451

public/sw.js

@@ -0,0 +1,6 @@
+self.addEventListener('install', () => {
+  self.skipWaiting();
+});
+self.addEventListener('activate', (event) => {
+  event.waitUntil(self.registration.unregister());
+});