ci(copilot): add workflow for Copilot setup steps

Author: mumenthalers

.github/workflows/copilot-setup-steps.yml

@@ -0,0 +1,36 @@
+# https://docs.github.com/en/enterprise-cloud@latest/copilot/how-tos/use-copilot-agents/coding-agent/customize-the-agent-environment
+# The copilot-setup-steps.yml workflow won't trigger unless it's present on your main branch.
+name: "Copilot Setup Steps"
+
+# Automatically run the setup steps when they are changed to allow for easy validation, and
+# allow manual testing through the repository's "Actions" tab
+on:
+  workflow_dispatch:
+  push:
+    paths:
+      - .github/workflows/copilot-setup-steps.yml
+  pull_request:
+    paths:
+      - .github/workflows/copilot-setup-steps.yml
+
+jobs:
+  # The job MUST be called `copilot-setup-steps` or it will not be picked up by Copilot.
+  copilot-setup-steps:
+    runs-on: ubuntu-latest
+
+    permissions:
+      contents: read
+
+    # You can define any steps you want, and they will run before the agent starts.
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+
+      - name: Setup Node and NPM Cache
+        uses: actions/setup-node@v4
+        with:
+          node-version-file: .nvmrc
+          cache: 'npm'
+
+      - name: GitHub registry Auth & Install Dependencies
+        run: npm ci