spike: remote composite action (throwaway branch)

.gitea/actions/hello/action.yml

@@ -0,0 +1,10 @@
+name: hello
+description: spike - proves remote composite action resolution
+inputs:
+  who: {required: true}
+runs:
+  using: composite
+  steps:
+    - shell: bash
+      run: echo "composite OK for $WHO on $(hostname) as $(id -un); node $(node -v 2>/dev/null || echo none)"
+      env: {WHO: "${{ inputs.who }}"}