Add Copilot PHPUnit setup workflow

Author: selul

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

@@ -0,0 +1,53 @@
+name: Copilot Setup Steps
+
+on:
+  workflow_dispatch:
+  push:
+    paths:
+      - .github/workflows/copilot-setup-steps.yml
+  pull_request:
+    paths:
+      - .github/workflows/copilot-setup-steps.yml
+
+jobs:
+  copilot-setup-steps:
+    runs-on: ubuntu-22.04
+    timeout-minutes: 30
+    permissions:
+      contents: read
+    services:
+      database:
+        image: mysql:latest
+        env:
+          MYSQL_DATABASE: wordpress_tests
+          MYSQL_ROOT_PASSWORD: root
+        ports:
+          - 3306:3306
+        options: >-
+          --health-cmd="mysqladmin ping -h 127.0.0.1 -uroot -proot"
+          --health-interval=10s
+          --health-timeout=5s
+          --health-retries=10
+    steps:
+      - name: Checkout source code
+        uses: actions/checkout@v4
+
+      - name: Setup PHP version
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: '8.0'
+          extensions: simplexml, mysql
+          tools: phpunit-polyfills:1.1
+          coverage: none
+
+      - name: Install WordPress test suite prerequisites
+        run: sudo apt-get update && sudo apt-get install -y subversion default-mysql-client
+
+      - name: Install WordPress Test Suite
+        run: composer install-wp-tests
+
+      - name: Install Composer dependencies
+        run: composer install --prefer-dist --no-progress --no-suggest
+
+      - name: Verify PHPUnit is available
+        run: composer phpunit -- --version