fix: JUnit version detection for multi-module Maven projects

- Check dependencyManagement section in pom.xml for test dependencies
- Recursively check submodule pom.xml files (test, tests, etc.)
- Change default fallback from JUnit 5 to JUnit 4 (more common in legacy)
- Add debug logging for framework detection decisions
- Fixes Bug #7: 64% of optimizations blocked by incorrect JUnit 5 detection

Author: mohamedashrraf222

codeflash/languages/java/config.py

@@ -240,7 +240,7 @@ def check_dependencies(deps_element, ns):
                         check_dependencies(deps, ns)
 
     except ET.ParseError:
-        logger.debug(f"Failed to parse pom.xml at {pom_path}")
+        logger.debug("Failed to parse pom.xml at %s", pom_path)
 
     # For multi-module projects, also check submodule pom.xml files
     if not (has_junit5 or has_junit4 or has_testng):