ci: install docker CLI before building images

.gitea/workflows/build-runner-images.yml

@@ -22,7 +22,12 @@ jobs:
       REGISTRY: forgejo.riotpiao.com
       IMAGE_BASE: forgejo.riotpiao.com/rock
     steps:
-      - name: Clone repository (base image, no Node.js required)
+      - name: Install docker CLI
+        run: |
+          apk update
+          apk add --no-cache docker
+
+      - name: Clone repository
         run: |
           git clone --depth 1 https://forgejo.riotpiao.com/rock/homelab.git .
 
@@ -31,7 +36,6 @@ jobs:
         run: |
           SHORT_SHA=$(git rev-parse --short HEAD)
           echo "short_sha=${SHORT_SHA}" >> $GITHUB_OUTPUT
-          echo "Got SHA: ${SHORT_SHA}"
 
       - name: Build all runner images (test on PR, push on main)
         run: |