Function normalize_tool_path_lexical 

pub fn normalize_tool_path_lexical(path: &str) -> String

Lexical (string-only) part of normalize_tool_path: MSYS2 drive prefix (Windows hosts only), separators, double slashes, trailing slash. Performs no filesystem access, so it is safe on persisted paths in TCC-standalone processes (launchd daemon, #356) and as a dedupe key where symlink resolution is not worth a realpath per entry.