Update theme selector and optimize button styling

Updated the theme selector to display the currently selected theme more clearly and enhance user-friendliness. Further, the button style is modernized with a class ensuring rounded edges for a sleeker appearance. These changes are applicable to the "ghost" button variant used for mode selection. Finally, the mode selection options utilize the MODES array for a dynamic approach, moving away from a fixed, hard-coded selection.

packages/ui/src/makerkit/sidebar.tsx

@@ -16,10 +16,9 @@ import {
   TooltipProvider,
   TooltipTrigger,
 } from '../shadcn/tooltip';
-import { cn } from '../utils';
+import { cn, isRouteActive } from '../utils';
 import { SidebarContext } from './context/sidebar.context';
 import { If } from './if';
-import isRouteActive from './is-route-active';
 import { SidebarConfigSchema } from './sidebar-schema';
 import { Trans } from './trans';