fix(ci): stagger builds in stages and add retry for Harbor load

Split 5 parallel build jobs into 3 stages (2+2+1) to avoid
overwhelming Harbor with concurrent image pulls. Add retry: 2
for transient failures.

Co-Authored-By: Claude <noreply@anthropic.com>

.gitlab-ci.yml

@@ -1,5 +1,7 @@
 stages:
-  - build
+  - build-1
+  - build-2
+  - build-3
 
 variables:
   HARBOR_REGISTRY: harbor-in-k3s.cheverjohn.me
@@ -10,10 +12,10 @@ variables:
   DOCKER_CERT_PATH: /certs/client
 
 .build-template: &build-template
-  stage: build
   image: docker:27
   services:
     - docker:27-dind
+  retry: 2
   before_script:
     - until docker info >/dev/null 2>&1; do echo "Waiting for Docker daemon..."; sleep 2; done
     - echo "$HARBOR_PASSWORD" | docker login $HARBOR_REGISTRY -u "$HARBOR_USER" --password-stdin
@@ -32,30 +34,35 @@ variables:
 
 build-gateway:
   <<: *build-template
+  stage: build-1
   variables:
     IMAGE_NAME: iloom-gateway
     DOCKERFILE_PATH: gateway/Dockerfile
 
 build-auth-service:
   <<: *build-template
+  stage: build-1
   variables:
     IMAGE_NAME: iloom-auth-service
     DOCKERFILE_PATH: auth-service/Dockerfile
 
 build-purchaser-service:
   <<: *build-template
+  stage: build-2
   variables:
     IMAGE_NAME: iloom-purchaser-service
     DOCKERFILE_PATH: purchaser-service/Dockerfile
 
 build-textile-service:
   <<: *build-template
+  stage: build-2
   variables:
     IMAGE_NAME: iloom-textile-service
     DOCKERFILE_PATH: textile-service/Dockerfile
 
 build-washing-service:
   <<: *build-template
+  stage: build-3
   variables:
     IMAGE_NAME: iloom-washing-service
     DOCKERFILE_PATH: washing-service/Dockerfile