refactor: update styling and color classes across components

- Changed error message styling in ICalImportModal to use new color classes.
- Updated task completion styling in TaskListView to use new success color classes.
- Modified selected styling in ContactListItem tests to reflect new background class.
- Adjusted duplicate warning styling in ContactImportDialog to use new warning color classes.
- Refactored background and border colors in CalendarInvitationBanner for various statuses.
- Updated email list item and viewer components to use new warning and success color classes.
- Refined styling for unread indicators in email components.
- Enhanced error fallback styling in error components to use new warning color classes.
- Updated filter rule modal button hover styles to use new destructive color classes.
- Added experimental feature descriptions in Plugins and Themes settings.
- Refined vacation settings validation warning styling to use new warning color classes.
- Updated toast component styles to use new color classes for different states.
- Introduced a new built-in theme 'Qui' with specific color variables.
- Adjusted email security status colors to use new warning color classes.

components/ui/toast.tsx

@@ -36,17 +36,17 @@ const icons = {
 };
 
 const iconContainerStyles = {
-  success: "bg-emerald-500 text-white",
-  error: "bg-red-500 text-white",
-  info: "bg-blue-500 text-white",
-  warning: "bg-amber-500 text-white",
+  success: "bg-success text-success-foreground",
+  error: "bg-destructive text-destructive-foreground",
+  info: "bg-info text-info-foreground",
+  warning: "bg-warning text-warning-foreground",
 };
 
 const progressBarStyles = {
-  success: "bg-emerald-500",
-  error: "bg-red-500",
-  info: "bg-blue-500",
-  warning: "bg-amber-500",
+  success: "bg-success",
+  error: "bg-destructive",
+  info: "bg-info",
+  warning: "bg-warning",
 };
 
 export function ToastItem({ toast, onClose }: ToastProps) {