Add copilot setup steps (#4398)

Author: trask

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

@@ -0,0 +1,40 @@
+name: Copilot Setup Steps
+
+# This workflow pre-installs dependencies for GitHub Copilot coding agent
+# to enable faster and more reliable development in Copilot's ephemeral environment.
+# See: https://docs.github.com/en/copilot/customizing-copilot/customizing-the-development-environment-for-copilot-coding-agent
+
+# 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:
+  push:
+    paths:
+      - .github/workflows/copilot-setup-steps.yml
+  pull_request:
+    paths:
+      - .github/workflows/copilot-setup-steps.yml
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+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
+ 
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+
+      - name: Set up JDK for running Gradle
+        uses: actions/setup-java@v4
+        with:
+          distribution: temurin
+          java-version: 17
+
+      - name: Setup Gradle
+        uses: gradle/actions/setup-gradle@v4
+
+      - name: Populate Gradle caches
+        run: ./gradlew classes testClasses assemble spotlessApply