Implement Role Management Features and UI Enhancements

- Introduced a new composable `useActiveRole` for managing user roles, including fetching role status and switching roles with server validation.
- Updated `RoleSwitcher.vue` to utilize the new composable, enhancing role selection with improved error handling and UI feedback.
- Added new API endpoints for role management, including fetching user role status and switching active roles.
- Enhanced product visibility logic to filter based on the user's active role, ensuring a tailored experience.
- Updated database schema to support last active role tracking for users, improving session management.
- Refined UI components across the application to reflect role-based changes and improve user experience.

app/components/UserMenu.vue

@@ -74,7 +74,6 @@ async function handleLogout() {
         <!-- Avatar with status ring (logged in indicator) -->
         <Avatar
           class="h-10 w-10 md:h-12 md:w-12 border-3 border-experimenta-purple shadow-lg bg-experimenta-accent ring-2 ring-experimenta-accent ring-offset-2 ring-offset-white dark:ring-offset-zinc-950">
-          <AvatarImage :src="undefined" :alt="extendedUser?.firstName || ''" />
           <AvatarFallback
             class="bg-experimenta-accent text-white font-bold text-sm md:text-base flex items-center justify-center w-full h-full">
             {{ userInitials }}