Replace the A2aHttpTransport stub with a working HTTP(S) transport that:
- Connects to remote A2A servers via HTTPS (with configurable TLS verification)
- Sends JSON-RPC 2.0 requests over HTTP POST
- Parses JSON-RPC responses into A2aResponse objects
- Handles HTTP errors (4xx/5xx) with structured error mapping
- Supports JWT Bearer token authentication
- Validates connection state before send operations
Added comprehensive test coverage:
- Behave BDD scenarios for validation and lifecycle testing
- Pytest unit tests with mocked HTTP responses covering success,
errors, network failures, auth tokens, and roundtrip serialization
CleverThis