get() ->
key,mods,event,shifted,base,is_paste
Read a keyboard event via the Kitty keyboard protocol
Returns the key name or character, modifier bitmask, event type
(1=press, 2=repeat, 3=release), shifted key, and base key.
Handles bracketed paste: the pasted text is returned as key with a
trailing is_paste flag set true (and the other fields nil), so callers
can insert it as literal text instead of dispatching it as a keypress.