feat(tkuser): 알림 시스템 이관 system1-factory → tkuser

- Phase 1: tkuser에 알림 CRUD, Push/ntfy 발송, 내부 알림 API 추가
- Phase 2: notifyHelper URL을 tkuser-api:3000으로 전환 (system2, tkpurchase, tksafety, system1)
- Phase 3: notification-bell.js API 도메인 tkuser로 변경 + 캐시 버스팅 v=4
- Phase 4: system1에서 알림 코드 제거 (routes, controllers, models, utils)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

system1-factory/web/push-sw.js

@@ -1,41 +0,0 @@
-// Push Notification Service Worker
-// 캐싱 없음 — Push 수신 전용
-
-self.addEventListener('push', function(event) {
-  var data = { title: '알림', body: '새 알림이 있습니다.', url: '/' };
-  if (event.data) {
-    try { data = Object.assign(data, event.data.json()); } catch(e) {}
-  }
-  event.waitUntil(
-    self.registration.showNotification(data.title, {
-      body: data.body,
-      icon: '/static/img/icon-192.png',
-      badge: '/static/img/badge-72.png',
-      data: { url: data.url || '/' },
-      tag: 'tk-notification-' + Date.now(),
-      renotify: true
-    })
-  );
-  // 메인 페이지에 뱃지 갱신 신호 전송
-  self.clients.matchAll({ type: 'window' }).then(function(clients) {
-    clients.forEach(function(client) {
-      client.postMessage({ type: 'NOTIFICATION_RECEIVED' });
-    });
-  });
-});
-
-self.addEventListener('notificationclick', function(event) {
-  event.notification.close();
-  var url = (event.notification.data && event.notification.data.url) || '/';
-  event.waitUntil(
-    self.clients.matchAll({ type: 'window' }).then(function(clients) {
-      for (var i = 0; i < clients.length; i++) {
-        if (clients[i].url.includes(self.location.origin)) {
-          clients[i].navigate(url);
-          return clients[i].focus();
-        }
-      }
-      return self.clients.openWindow(url);
-    })
-  );
-});

system1-factory/web/static/js/tkfb-core.js

@@ -299,7 +299,7 @@ async function initAuth() {
 /* ===== 알림 벨 ===== */
 function _loadNotificationBell() {
     const s = document.createElement('script');
-    s.src = (location.hostname.includes('technicalkorea.net') ? 'https://tkds.technicalkorea.net' : location.protocol + '//' + location.hostname + ':30000') + '/shared/notification-bell.js?v=3';
+    s.src = (location.hostname.includes('technicalkorea.net') ? 'https://tkds.technicalkorea.net' : location.protocol + '//' + location.hostname + ':30000') + '/shared/notification-bell.js?v=4';
     document.head.appendChild(s);
 }