[Build] feat: Add Settings page with full CRUD for Business Units, Roles, and Users

## GitHub Update **Repository:** [MKWcorp/hrisnextgen](https://github.com/MKWcorp/hrisnextgen) **Author:** multimediadrw **Date:** 10/26/2025, 11:31:03 PM **Commit:** [`744115c`](https://github.com/MKWcorp/hrisnextgen/commit/744115c895bc9424ab5da76e2d7763f0d5ed6818) ### Commit Message feat: Add Settings page with full CRUD for Business Units, Roles, and Users - Created Settings page at /dashboard/settings with tabbed interface - Implemented full CRUD operations for Business Units, Roles, and Users - Added Settings menu item to Navigation component - Created API endpoints for Roles and Users: - POST /api/roles - Create new role - PUT /api/roles/[id] - Update role - DELETE /api/roles/[id] - Delete role - POST /api/users - Create new user with email validation - PUT /api/users/[id] - Update user with duplicate email check - DELETE /api/users/[id] - Delete user - Updated Users GET endpoint to include relations (roles, business_units) - Fixed Next.js 15 compatibility: params now async (Promise type) - Features: - Form validation and error handling - Edit mode with pre-filled forms - Delete confirmations - Loading states - Responsive card-based UI - User count badges on tabs - User avatars with initials - Build successful, production ready --- _This story was imported from historical commits._