chore: slim build.yml to use shared docker-build action

.gitea/workflows/build.yml

@@ -1,4 +1,4 @@
-name: Build and publish
+name: build
 
 on:
   push:
@@ -7,17 +7,6 @@ on:
   pull_request:
     branches: [main]
 
-# Required secrets:
-#   REGISTRY        git.librete.ch
-#   REGISTRY_USER   libretech-bot
-#   REGISTRY_PASS   bot PAT (write:package; bot is in libreshop Owners team)
-# Required variable:
-#   PUBLISH_ENABLED "true" to actually push (off = build-only on PRs)
-#
-# Image: git.librete.ch/libreshop/nginx
-#   main pushes  → :main + :sha-<short>
-#   tag pushes   → :<tag> + :latest
-
 jobs:
   build:
     runs-on: ubuntu-latest
@@ -27,29 +16,10 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
-      - uses: docker/setup-buildx-action@v3
-
-      - name: Login (only when publishing)
-        if: ${{ vars.PUBLISH_ENABLED == 'true' }}
-        uses: docker/login-action@v3
+      - uses: libreshop/actions/.gitea/actions/docker-build@main
         with:
           registry: ${{ secrets.REGISTRY }}
-          username: ${{ secrets.REGISTRY_USER }}
-          password: ${{ secrets.REGISTRY_PASS }}
+          registry_user: ${{ secrets.REGISTRY_USER }}
+          registry_pass: ${{ secrets.REGISTRY_PASS }}
+          publish: ${{ github.event_name == 'push' && vars.PUBLISH_ENABLED == 'true' }}
 
-      - id: meta
-        uses: docker/metadata-action@v5
-        with:
-          images: ${{ secrets.REGISTRY }}/libreshop/nginx
-          tags: |
-            type=ref,event=branch
-            type=ref,event=tag
-            type=sha,format=short
-            type=raw,value=latest,enable=${{ startsWith(github.ref, 'refs/tags/') }}
-
-      - uses: docker/build-push-action@v6
-        with:
-          context: .
-          push: ${{ vars.PUBLISH_ENABLED == 'true' && github.event_name == 'push' }}
-          tags: ${{ steps.meta.outputs.tags }}
-          labels: ${{ steps.meta.outputs.labels }}