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>

docker-compose.yml

@@ -103,14 +103,7 @@ services:
       - REDIS_PORT=6379
       - WEATHER_API_URL=${WEATHER_API_URL:-}
       - WEATHER_API_KEY=${WEATHER_API_KEY:-}
-      - VAPID_PUBLIC_KEY=${VAPID_PUBLIC_KEY}
-      - VAPID_PRIVATE_KEY=${VAPID_PRIVATE_KEY}
-      - VAPID_SUBJECT=${VAPID_SUBJECT:-mailto:admin@technicalkorea.net}
       - INTERNAL_SERVICE_KEY=${INTERNAL_SERVICE_KEY}
-      - NTFY_BASE_URL=${NTFY_BASE_URL:-http://ntfy:80}
-      - NTFY_PUBLISH_TOKEN=${NTFY_PUBLISH_TOKEN}
-      - NTFY_EXTERNAL_URL=${NTFY_EXTERNAL_URL:-https://ntfy.technicalkorea.net}
-      - TKFB_BASE_URL=${TKFB_BASE_URL:-https://tkfb.technicalkorea.net}
     volumes:
       - system1_uploads:/usr/src/app/uploads
       - system1_logs:/usr/src/app/logs
@@ -274,6 +267,14 @@ services:
       - DB_PASSWORD=${MYSQL_PASSWORD}
       - DB_NAME=${MYSQL_DATABASE:-hyungi}
       - SSO_JWT_SECRET=${SSO_JWT_SECRET}
+      - VAPID_PUBLIC_KEY=${VAPID_PUBLIC_KEY}
+      - VAPID_PRIVATE_KEY=${VAPID_PRIVATE_KEY}
+      - VAPID_SUBJECT=${VAPID_SUBJECT:-mailto:admin@technicalkorea.net}
+      - INTERNAL_SERVICE_KEY=${INTERNAL_SERVICE_KEY}
+      - NTFY_BASE_URL=${NTFY_BASE_URL:-http://ntfy:80}
+      - NTFY_PUBLISH_TOKEN=${NTFY_PUBLISH_TOKEN}
+      - NTFY_EXTERNAL_URL=${NTFY_EXTERNAL_URL:-https://ntfy.technicalkorea.net}
+      - TKFB_BASE_URL=${TKFB_BASE_URL:-https://tkfb.technicalkorea.net}
     volumes:
       - system1_uploads:/usr/src/app/uploads
     depends_on: