demo: runs-on fenced (crunchy VM runner)

.forgejo/workflows/ci.yml

@@ -0,0 +1,12 @@
+name: fenced-demo
+on: [push]
+jobs:
+  where-am-i:
+    runs-on: fenced
+    steps:
+      - name: prove this ran on the crunchy fenced runner
+        run: |
+          echo "kernel:   $(uname -a)"
+          echo "egress-ip: $(curl -s --max-time 8 https://api.ipify.org || echo n/a)"
+          echo "container-host-check: /proc/1 sees $(cat /etc/hostname)"
+          echo "docker-in-job: $(docker version --format '{{.Server.Version}}' 2>/dev/null || echo 'no docker in job (expected)')"