Pass docker socket to job containers, use docker:24 for image builds

.gitea/workflows/build-runner.yml

@@ -10,6 +10,10 @@ on:
 jobs:
   build:
     runs-on: ubuntu-latest
+    container:
+      image: docker:24
+      volumes:
+        - /var/run/docker.sock:/var/run/docker.sock
     steps:
       - name: Checkout
         uses: actions/checkout@v4

ansible/roles/gitea-runner/templates/config.yml.j2

@@ -15,3 +15,4 @@ cache:
 container:
   network: bridge
   force_pull: false    # reuse cached images to speed up builds
+  docker_sock_path: /var/run/docker.sock