Function dispatch_dynamic_interaction 

pub async fn dispatch_dynamic_interaction(
    backend: &dyn InteractionBackend,
    tool_name: &str,
    tool_call_id: &str,
    arguments: &Value,
    stage_name: &str,
) -> Option<String>

Dispatch a single dynamic-interaction tool call.

Returns Some(result_string) if tool_name is one of present_for_review / ask_user_text / ask_user_choice / ask_user_confirm (and was therefore handled here); returns None for any other tool name so the caller can fall through to normal tool dispatch.