Function detect_build_system 

pub fn detect_build_system(
    project_root: &Path,
    override_build_system: Option<&str>,
) -> DetectionResult

Detect the build system for a JVM project.

Scans for marker files starting at project_root. If override_build_system is provided, it takes precedence over auto-detection.

Priority (when multiple build systems detected)

Bazel > Gradle > Maven > sbt

This priority reflects that Bazel projects often also contain pom.xml or build.gradle for IDE compatibility, so the Bazel marker should win.