Add PHP lint workflow

Adds GitHub Actions workflow to validate PHP syntax across all PHP files in the repository. The workflow runs on push and pull requests, checking PHP 7.4 and 8.0 compatibility.

Author: borkweb

.github/workflows/php-lint.yml

@@ -0,0 +1,59 @@
+name: PHP Code Linting
+
+on:
+  push:
+    branches:
+      - trunk
+      - 'feature/**'
+      - 'release/**'
+    # Only run if PHP-related files changed.
+    paths:
+      - '.github/workflows/php-lint.yml'
+      - '**.php'
+      - 'phpcs.xml.dist'
+      - 'phpstan.neon.dist'
+      - 'composer.json'
+      - 'composer.lock'
+  pull_request:
+    # Only run if PHP-related files changed.
+    paths:
+      - '.github/workflows/php-lint.yml'
+      - '**.php'
+      - 'phpcs.xml.dist'
+      - 'phpstan.neon.dist'
+      - 'composer.json'
+      - 'composer.lock'
+    types:
+      - opened
+      - reopened
+      - synchronize
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: ${{ github.ref != 'refs/heads/main' }}
+
+jobs:
+  php-lint:
+    name: PHP
+    runs-on: ubuntu-latest
+    timeout-minutes: 20
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: shivammathur/setup-php@v2
+        with:
+          php-version: 'latest'
+
+      - name: Validate Composer configuration
+        run: composer validate
+
+      - name: Install PHP dependencies
+        uses: ramsey/composer-install@3cf229dc2919194e9e36783941438d17239e8520
+        with:
+          composer-options: '--prefer-dist'
+
+      - name: PHPStan
+        run: composer phpstan
+
+      - name: PHP Code Sniffer
+        run: composer phpcs