Function walk_module_tree 

pub fn walk_module_tree<E>(
    root: &Path,
    visitor: &mut dyn FnMut(&Path, u64) -> Result<(), E>,
) -> Result<TreeStats, WalkError<E>>

Walks every regular file under root, enforcing containment and metadata exclusion. Calls visitor for each file with its path and size. Returns aggregate statistics.

The walk enforces these rules.

• Entries named .git or .sprocket are skipped.
• Any symbolic link is rejected with ModuleWalkError::Symlink.
• Only regular files are visited.