Function run_self_update 

pub fn run_self_update(
    yes: bool,
    check_only: bool,
    non_interactive: bool,
) -> Result<()>

Run yui self-update. Flags map directly onto kaishin’s UpdateOptions:

• yes skips the confirmation prompt.
• check_only reports availability and exits without installing.
• non_interactive makes kaishin bail out (rather than prompt) when stdin isn’t a tty; only meaningful together with yes.