Build image from remote git context on Forgejo runner

.forgejo/workflows/build-local-image.yml

@@ -10,19 +10,8 @@ jobs:
   build:
     runs-on: nix-host
     steps:
-      - name: Fetch repository archive
-        run: |
-          set -euo pipefail
-          curl -fsSL "https://git.centraworks.net/api/v1/repos/centra/lightscale-admin/archive/${GITHUB_SHA}.tar.gz?rev=${GITHUB_SHA}" \
-            | tar -xz --strip-components=1
-
-      - name: Validate workspace
-        run: |
-          set -euo pipefail
-          test -f Dockerfile
-
       - name: Build local image on runner host
-        run: docker build --pull -t lightscale-admin:local .
+        run: docker build --pull -t lightscale-admin:local "https://git.centraworks.net/centra/lightscale-admin.git#${GITHUB_SHA}"
 
       - name: Show built image
         run: docker image ls lightscale-admin:local