- Introduced `changeMarginMode` method in `ExchangeAdapter` interface to allow margin mode adjustments.
- Implemented the `changeMarginMode` method in `StandxExchangeAdapter` to interact with the gateway for changing margin modes.
- Added corresponding `changeMarginMode` method in `StandxGateway` to handle API requests for margin mode changes.
- Enhanced `MakerPointsEngine` to ensure isolated margin mode before order placement, with appropriate logging and defense mode activation if the change fails.
- Created tests for margin mode functionality to validate behavior under different scenarios.