feat: add HTTP/WebSocket transport for remote ACP agents by 3coins · Pull Request #68 · agentclientprotocol/python-sdk

- Update README.md to mention HTTP/WebSocket transport and examples
- Add HTTP/WebSocket section to docs/quickstart.md with usage examples
- Add dedicated docs/http-transport.md with architecture, API reference,
  and server/client examples
- Add http-transport.md to mkdocs.yml navigation
- Add tests/test_http_transport.py with 13 tests covering:
  - WebSocketStreamAdapter lifecycle (start, close, double-start)
  - Bidirectional message flow (receive → reader, writer → send)
  - EOF handling on WebSocket disconnect
  - StarletteWebSocketWrapper delegation
  - End-to-end agent ↔ client communication over WebSocket adapters