- Add SessionManager for managing user sessions (singleton pattern)
- Add BIPUsersDAO for database authentication
- Add LoginDialog component for username/password login
- Add UserSelectionDialog component for admin user selection
- Support silent login by computer name
- Implement main page with navigation to Extractor and Cleaner
Database:
- Table: dbo_BIPUsers
- Fields: UserName, Password, UserType, ComputerNmae
UI Flow:
1. Silent login on startup via computer name
2. Show login dialog if silent login fails
3. Display main page with user info and navigation
4. Support logout and re-login
