fix(ui): improve group selector dropdown width and visibility

- Increase Select dropdown max-width from 320px to 480px for better content display
- Change KeysView group selector from fixed 256px to adaptive 280-480px width
- Make group switch icon always visible (60% opacity, 100% on hover)
- Allow group description to wrap to 2 lines instead of truncating
- Improve user experience for group selection in API keys page

frontend/src/components/common/Select.vue

@@ -434,7 +434,7 @@ onUnmounted(() => {
 
 <style>
 .select-dropdown-portal {
-  @apply w-max min-w-[160px] max-w-[320px];
+  @apply w-max min-w-[200px] max-w-[480px];
   @apply bg-white dark:bg-dark-800;
   @apply rounded-xl;
   @apply border border-gray-200 dark:border-dark-700;