Transport Layer Implementation

[mo-jaber]

https://github.com/bsv-blockchain/py-middleware/milestone/2

Port the ExpressTransport class and HTTP handling logic

Tasks:

2.1 Implement Python Transport interface/abstract base class
2.2 Port ExpressTransport class for chosen web framework
2.3 Implement request/response payload building functions
2.4 Port HTTP header parsing and BRC-104 compliance
2.5 Handle multipart/form-data and various content types
2.6 Implement response interception and modification