tmux set the outer terminal title from `set-titles-string '#h:#W'`, which
is what Hyprland reads for the group bar label. herdr had no equivalent,
so grouped terminals kept whatever the shell or ssh last set - most
visibly wrong when connected to a remote machine.
herdr now renders `ui.window_title` on the server, so mirror the tmux
line. herdr's own default matches, but setting it here keeps the group
bar correct regardless of what upstream picks as its default.
David Heinemeier Hansson
0b670cd13e