fix(deploy): CI에서 직접 백엔드 서비스 재시작 (#33)

Co-authored-by: htlee <htlee@gcsc.co.kr>
Co-committed-by: htlee <htlee@gcsc.co.kr>

.gitea/workflows/deploy.yml

@@ -80,7 +80,25 @@ jobs:
           cp deploy/kcg-backend-watcher.service $DEPLOY_DIR/kcg-backend-watcher.service
           cp deploy/kcg-backend-watcher.path $DEPLOY_DIR/kcg-backend-watcher.path
 
-          # JAR 교체 + 재시작 트리거
+          # JAR 교체
           cp backend/target/kcg.jar $DEPLOY_DIR/kcg.jar
-          date '+%s' > $DEPLOY_DIR/.deploy-trigger
           echo "Backend deployed at $(date '+%Y-%m-%d %H:%M:%S')"
+
+      - name: Restart backend service
+        run: |
+          # systemd 서비스 파일 갱신 + 백엔드 재시작 (호스트 네임스페이스)
+          nsenter -t 1 -m -- /bin/bash -c '
+            DEPLOY_DIR=/devdata/services/kcg/backend
+            SYSTEMD_DIR=/etc/systemd/system
+            CHANGED=0
+            for f in kcg-backend.service kcg-backend-watcher.service kcg-backend-watcher.path; do
+              if [ -f "$DEPLOY_DIR/$f" ] && ! diff -q "$DEPLOY_DIR/$f" "$SYSTEMD_DIR/$f" >/dev/null 2>&1; then
+                cp "$DEPLOY_DIR/$f" "$SYSTEMD_DIR/$f"
+                CHANGED=1
+              fi
+            done
+            [ "$CHANGED" = "1" ] && systemctl daemon-reload
+            systemctl restart kcg-backend
+            sleep 5
+            systemctl is-active kcg-backend && echo "Backend restarted successfully" || echo "Backend failed to start"
+          '