check-ghostty-update

Check whether ghostty (the terminal core termio embeds via the termio-sh/libghostty-swift fork) has shipped anything worth pulling since the binary termio is currently pinned to. Resolves the pinned ghostty sha, diffs it against ghostty main, filters the gap for changes that actually reach termio's embedded VT/terminal core (dropping app-chrome / packaging / i18n noise), and gives a keep-waiting-or-pull-now verdict.…