Bell: raise window urgency / request user attention

I'm looking to switch from Ghostty to Rio, but I'm missing one piece of bell/notification behavior that Ghostty has and that I currently rely on.

Ghostty has a built-in, shell-integration-based feature for exactly this case — a long-running command finishes in a window that isn't focused:

notify-on-command-finish = unfocused notify-on-command-finish-action = bell notify-on-command-finish-after = 5s

When a command takes longer than notify-on-command-finish-after and the window is unfocused, Ghostty rings the bell (which then raises the window's urgency hint / requests attention from the compositor). This lets my status bar (Waybar) flash the workspace indicator so I know a background task finished, without polling every terminal window.

Rio's [bell] config only controls audio and visual (screen flash) — there's nothing that reaches the window manager/compositor:

[bell] visual = false audio = true