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.

server/database/migrations/0003_charming_zzzax.sql

@@ -0,0 +1 @@
+ALTER TABLE "users" ADD COLUMN "last_active_role_code" "role_code";