update workflow to use host rootless podman

.forgejo/workflows/podman-demo.yml

@@ -4,16 +4,24 @@ on: [push, pull_request]
 jobs:
   test-rootless:
     runs-on: [ci]
+
+    # Point all steps at the host's rootless Podman socket
+    env:
+      PODMAN_HOST: unix:///run/user/1001/podman/podman.sock
+
     steps:
       - name: Checkout code
         uses: actions/checkout@v4
 
-      - name: Test Podman rootless
+      - name: Use host rootless Podman
         run: |
-          podman --version
+          set -euo pipefail
-          podman run --rm alpine:3.20 echo "Hello from rootless Podman!"
+          podman info --format '{{.Host.RemoteSocket.Path}} (remote={{.Host.RemoteSocket.Exists}})'
+          podman version
+          podman run --rm alpine:3.20 echo "Hello from host rootless Podman!"
 
       - name: Build and run a container
         run: |
+          set -euo pipefail
           podman build -t test-image .
           podman run --rm test-image