Function unit_path_matches 

pub fn unit_path_matches(rel_path: &Path, qualified_name: &str) -> bool

v0.9.1: shared between source-unit and test-unit path validation. The caller decides which root to strip from the file path before calling.

A file belongs to qualified_name when it is either the single file <name>.bynk (single_file_match: stem parts == name parts) or one file of the directory layout <name>/*.bynk (multi_file_match: parent-dir parts == name parts). These two branches are the single source of truth the v0.132 barrel trigger reads via is_multi_file_layout.