alt_screen(
opts) ->state
Enter the alternate screen with KKBP and bracketed paste enabled
Saves the cursor position, switches to the alt screen and blanks it,
enables KKBP and bracketed paste, and hides the cursor. Returns a
state object with a state:done() method that restores everything.
opts.query_cursor (default true): when false, skips the ESC[6n
cursor-position query. The query reads stdin through buffered stdio,
so callers that then read input via a raw lev.fd_reader must pass
false or those reads will miss buffer-swallowed keystrokes.