probe: dump runner env

.github/workflows/probe.yml

@@ -0,0 +1,14 @@
+name: probe
+on: [push]
+jobs:
+  env:
+    runs-on: ubuntu-latest
+    steps:
+      - name: dump the forge-identifying environment
+        run: |
+          echo "--- GITHUB_* ---"
+          env | grep -E '^GITHUB_' | sort
+          echo "--- GITEA_/FORGEJO_/ACTIONS_ ---"
+          env | grep -E '^(GITEA_|FORGEJO_|ACTIONS_|CI=|RUNNER_)' | sort
+          echo "--- clients present ---"
+          for b in gh curl jq node stoke; do printf '%s: %s\n' "$b" "$(command -v $b || echo ABSENT)"; done