Issue description

tmux-3.6a tty-keys.sh fails:

+ make -C regress
...
sh tty-keys.sh
[FAIL] \\0330x7F -> M-BSpace (Got: 'M-C-?')

Required information

• tmux version (tmux -V): tmux 3.6a
• Platform (uname -sp): Linux unknown
• Terminal in use (xterm, rxvt, etc): console
• $TERM inside tmux (echo $TERM): screen-256color
• $TERM outside tmux (echo $TERM): xterm-256color