fix(docker): shared 모듈 경로 심링크 추가 — 4개 서비스 Dockerfile

shared/middleware/pagePermission.js를 ../../../shared/로 참조하면
Docker 컨테이너 내부에서 /usr/src/shared/를 찾아 MODULE_NOT_FOUND 발생.
ln -s /usr/src/app/shared /usr/src/shared 심링크로 해결.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

user-management/api/Dockerfile

@@ -10,6 +10,7 @@ RUN npm install --omit=dev
 COPY user-management/api/ ./
 COPY user-management/migrations/ /usr/src/migrations/
 
+RUN ln -s /usr/src/app/shared /usr/src/shared
 RUN mkdir -p /usr/src/app/uploads/consumables && \
     chown -R node:node /usr/src/app /usr/src/migrations
 USER node