ci: add codecoverage action to test workflow (#117)

Integrate ggilder/codecoverage@v1 to annotate pull requests with missing
test coverage. The action processes the clover.xml coverage report
generated by PHPUnit and highlights lines that lack test coverage
directly in PR reviews.

---------

Co-authored-by: Claude <noreply@anthropic.com>

Author: deviantintegral

.github/workflows/test.yml

@@ -48,6 +48,13 @@ jobs:
       - name: Run tests
         run: vendor/bin/phpunit --coverage-clover build/logs/clover.xml
 
+      - name: Code Coverage Annotation
+        uses: ggilder/codecoverage@v1
+        with:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          COVERAGE_FILE_PATH: build/logs/clover.xml
+          COVERAGE_FORMAT: clover
+
       - name: Upload test results
         if: always()
         uses: actions/upload-artifact@b7c566a772e6b6bfb58ed0dc250532a479d7789f # v6