ci: drop registry push, just build the image

Renamed pipeline from "Build and Push to Registry" to "Build Image".
Dropped the registry login/push/logout steps (needed secrets that
don't exist on the new instance) and the hardcoded git clone against
gitea.servernah.com in favor of actions/checkout, which works
regardless of which Gitea instance runs it.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

.gitea/workflows/publish.yaml

@@ -1,36 +1,24 @@
-name: Build and Push to Registry
+name: Build Image
 on: [push]
 
 jobs:
-  build-and-push:
+  build:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout code
-        run: |
-          git clone https://gitea.servernah.com/${{ gitea.repository }} .
-
-      - name: Log in to Custom Registry
-        run: |
-          echo "${{ secrets.REGISTRY_PASSWORD }}" | docker login ${{ secrets.REGISTRY_URL }} -u "${{ secrets.REGISTRY_USERNAME }}" --password-stdin
+        uses: actions/checkout@v4
 
       - name: Set up Docker Tags
         id: vars
         run: |
           # Use the short git commit hash as a tag
-          echo "sha_short=$(git rev-parse --short HEAD)" >> $GITHUB_OUTPUT
-          # Define the full image name
-          echo "image_path=${{ secrets.REGISTRY_URL }}/servernah/devops-website" >> $GITHUB_OUTPUT
+          echo "sha_short=$(git rev-parse --short HEAD)" >> "$GITHUB_OUTPUT"
+          echo "image_path=devops-website" >> "$GITHUB_OUTPUT"
 
       - name: Build Docker Image
         run: |
           docker build -t ${{ steps.vars.outputs.image_path }}:${{ steps.vars.outputs.sha_short }} .
           docker tag ${{ steps.vars.outputs.image_path }}:${{ steps.vars.outputs.sha_short }} ${{ steps.vars.outputs.image_path }}:latest
 
-      - name: Push Image to Registry
-        run: |
-          docker push ${{ steps.vars.outputs.image_path }}:${{ steps.vars.outputs.sha_short }}
-          docker push ${{ steps.vars.outputs.image_path }}:latest
-
-      - name: Cleanup
-        if: always()
-        run: docker logout ${{ secrets.REGISTRY_URL }}
+      - name: Show built image
+        run: docker images ${{ steps.vars.outputs.image_path }}