도커백엔드 수정

docker/deploy/backend.Dockerfile

@@ -27,8 +27,8 @@ RUN npm run build
 FROM base AS runner
 ENV NODE_ENV=production
 
-# Create non-root user
-RUN groupadd -r appgroup && useradd -r -g appgroup appuser
+# Create non-root user with specific UID/GID
+RUN groupadd -r appgroup --gid 1000 && useradd -r -g appgroup --uid 1000 appuser
 
 # Copy production node_modules
 COPY --from=deps /app/node_modules ./node_modules