Add modular PHP checks

modules/php.sh

@@ -0,0 +1,64 @@
+#!/bin/bash
+set -euo pipefail
+
+echo "========================"
+echo " Davidson CI - PHP"
+echo "========================"
+
+PHP_COUNT="${DAVIDSON_PHP_COUNT:-0}"
+
+if [ "$PHP_COUNT" -eq 0 ]; then
+    echo "No PHP files detected - skipping PHP module"
+    exit 0
+fi
+
+echo
+echo "PHP files detected: $PHP_COUNT"
+echo
+
+echo "→ PHP syntax"
+find . \
+    -type f \
+    -name "*.php" \
+    -not -path "./vendor/*" \
+    -print0 |
+xargs -0 -n1 php -l
+
+echo
+echo "→ Composer"
+
+if [ -f composer.json ]; then
+    composer validate --no-check-publish
+
+    if [ -f composer.lock ]; then
+        composer install \
+            --no-interaction \
+            --prefer-dist \
+            --no-progress
+    else
+        echo "composer.json found but no composer.lock"
+    fi
+else
+    echo "No composer.json - skipping Composer"
+fi
+
+echo
+echo "→ PHPStan"
+
+if [ -x vendor/bin/phpstan ]; then
+    vendor/bin/phpstan analyse
+else
+    echo "PHPStan not installed - skipping"
+fi
+
+echo
+echo "→ PHPUnit"
+
+if [ -x vendor/bin/phpunit ]; then
+    vendor/bin/phpunit
+else
+    echo "PHPUnit not installed - skipping"
+fi
+
+echo
+echo "PHP module completed successfully"