Improve BLE error handling and clean up peripheral delegate references

[sameerasw]

This pull request introduces several improvements to the Bluetooth Low Energy (BLE) central manager logic in BLECentralManager.swift, primarily focusing on better resource management and enhanced error handling during BLE operations. It also bumps the app’s version and build numbers in the Xcode project configuration.

BLE resource management and error handling improvements:

• Ensured the delegate property of CBPeripheral is set to nil in all disconnection and failure scenarios to prevent potential retain cycles and unintended callbacks. [1] [2] [3] [4] [5]
• Added comprehensive error logging for BLE delegate methods, including service and characteristic discovery, value updates, notification state changes, descriptor operations, and RSSI reads, to aid in debugging and monitoring BLE interactions. [1] [2] [3]
• Improved robustness by safely unwrapping and validating CBService and CBCharacteristic objects before use, reducing the risk of runtime errors.

Project configuration updates:

• Incremented the CURRENT_PROJECT_VERSION from 30 to 31 and updated the MARKETING_VERSION from 4.0.0 to 4.0.1 in AirSync.xcodeproj/project.pbxproj to reflect a new release. [1] [2] [3] [4] [5] [6]