feat: enhance betslip embed and add new endpoints for betslip management

- Updated the betslip embed to capitalize the user's team choice for better presentation.
- Introduced new API endpoints for managing betslips, including fetching all betslips, user-specific betslips, and active betslips.
- Added functionality to clear pending bets and close outstanding bets for matches.
- Enhanced error handling and response structures for better user experience and API consistency.