fix(deploy): SSH 호스트 IP 동적 감지 (ip route default gateway)

하드코딩 172.17.0.1 → ip route에서 default gateway 자동 추출.
CI 컨테이너가 services_devnet(172.18.x.x) 사용 시에도 정상 동작.

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

.gitea/workflows/deploy.yml

@@ -89,8 +89,8 @@ jobs:
           mkdir -p ~/.ssh
           echo "$DEPLOY_KEY" > ~/.ssh/id_deploy
           chmod 600 ~/.ssh/id_deploy
-          # Docker 컨테이너 → 호스트: bridge gateway(172.17.0.1) 경유
-          DOCKER_HOST_IP=172.17.0.1
+          # Docker 컨테이너 → 호스트: services_devnet gateway 경유
+          DOCKER_HOST_IP=$(ip route | awk '/default/ {print $3}')
           ssh-keyscan $DOCKER_HOST_IP >> ~/.ssh/known_hosts 2>/dev/null || true
 
           SSH_CMD="ssh -i ~/.ssh/id_deploy -o StrictHostKeyChecking=no root@$DOCKER_HOST_IP"