fix: enable xdebug coverage driver in CI tests

- Change coverage from 'none' to 'xdebug' in test jobs
- Fixes PHPUnit warning 'No code coverage driver available'
- Prevents test failures due to failOnWarning=true setting

Author: calliostro

.github/workflows/ci.yml

@@ -41,7 +41,7 @@ jobs:
       with:
         php-version: ${{ matrix.php-version }}
         extensions: dom, curl, libxml, mbstring, zip, json
-        coverage: none
+        coverage: xdebug
         tools: composer:v2
 
     - name: Cache Composer packages