Function edit_code 

pub fn edit_code(
    project_root: &Path,
    params: &EditCodeInput,
    propagation_state: &Mutex<PropagationState>,
    lsp_analyzer: &Mutex<Option<Box<dyn Analyzer + Send>>>,
) -> Result<EditCodeOutput, String>

Applies line-hash anchored edits and records propagation review events.

Errors

Returns an error if an edit is invalid or cannot be applied.