fix(tkuser): Dockerfile에 migrations 디렉토리 COPY 추가

컨테이너 내부에서 /usr/src/migrations/ 경로 참조하나
user-management/migrations/가 복사되지 않아 startup crash 발생

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

user-management/api/Dockerfile

@@ -8,9 +8,10 @@ COPY user-management/api/package*.json ./
 RUN npm install --omit=dev
 
 COPY user-management/api/ ./
+COPY user-management/migrations/ /usr/src/migrations/
 
 RUN mkdir -p /usr/src/app/uploads/consumables && \
-    chown -R node:node /usr/src/app
+    chown -R node:node /usr/src/app /usr/src/migrations
 USER node
 
 EXPOSE 3000