feat: Add language switcher functionality to the lang-label button

[kosa12]

modules/bar.py:

• Clicking the button executes hyprctl switchxkblayout all next to cycle through available keyboard layouts.
• The on_language_switch method updates the button's label and tooltip dynamically based on Hyprland's active layout event.

[Axenide]

Nice. Where do you set which languages are available?

[kosa12]

in the hyprland.conf you can set the language layout like this:

input {
    kb_layout = us,de,fr
    kb_options = grp:win_space_toggle   // or whatever 
}

And i just added this to have a mouse button support too, not just a keyboard one