Fix Gitea CI external action dependency

.gitea/workflows/build-and-deploy.yml

@@ -52,8 +52,10 @@ jobs:
       - name: Ensure Docker CLI is available
         run: |
           if ! command -v docker >/dev/null 2>&1; then
-            apt-get update -qq
-            apt-get install -y -qq docker.io
+            echo "::error::Docker CLI is not available in this Gitea runner image."
+            echo "::error::Configure the runner label used by this job to an image that already includes Docker CLI, for example ubuntu-latest:docker://catthehacker/ubuntu:act-latest."
+            echo "::error::The current runner maps ubuntu-latest to node:20-bookworm, and this job cannot install docker.io because the job container has no external DNS."
+            exit 1
           fi
           docker --version
           docker info >/dev/null
@@ -210,7 +212,12 @@ jobs:
       - name: Install SSH client
         if: steps.check-creds.outputs.skip == 'false'
         run: |
-          apt-get update -qq && apt-get install -y -qq openssh-client
+          if ! command -v ssh >/dev/null 2>&1 || ! command -v scp >/dev/null 2>&1; then
+            echo "::error::OpenSSH client tools are not available in this Gitea runner image."
+            echo "::error::Use a runner image that already includes ssh and scp; installing packages from apt is not reliable because the job container has no external DNS."
+            exit 1
+          fi
+          ssh -V
 
       - name: Set up SSH key
         if: steps.check-creds.outputs.skip == 'false'