Animation: bounce when the focus is on the first/last column and we attempt to focus to the left/right

[bphenriques]

Similar to mobile devices, when the current focus is the first/last column bounce the view a bit if we attempt to go left/right (respectively) to have a visual indicator that we have reached the end.

Gives a bit of flair and makes the experience more familiar. Had this idea while I was iterating my keybindings.

Notes:

• This animation doesn't make sense when the action is to loop through the list of focused columns.
• This might apply to workspaces as well

[bphenriques]

Unsure if this behaviour can be achieved already as per the wiki: https://github.com/YaLTeR/niri/wiki/Configuration:-Animations

Separate discussion but when I read it, I am unsure which animations are new or just explain the default ones (given that Niri uses lots of animation already).

[YaLTeR]

We already do this for touchpad gestures, and for keyboard I have a feeling that it'll be more annoying than useful, but not sure. There are other ways planned to indicate this, like adding window positions to IPC which will allow to make bar widgets, or an overview.

[bphenriques]

I understand, the intent was to make it more consistent with the gestures I already use. Noticed the lack of it when I was moving between columns using the keyboard