Summary

Update websocket_facade to return i_protocol_client/i_protocol_server interfaces instead of messaging_ws_client/messaging_ws_server types. This aligns with the pattern already used by tcp_facade and udp_facade (PR #656).

What

• Create ws_client_adapter implementing i_protocol_client
• Create ws_server_adapter implementing i_protocol_server
• Update websocket_facade.h return types
• Update dependent tests and samples

Why

Part of EPIC #577: Apply Facade pattern to reduce protocol header complexity.

• Reduces public API surface
• Provides unified interface across all protocols
• Enables protocol-agnostic client/server usage

Acceptance Criteria

• websocket_facade::create_client() returns i_protocol_client
• websocket_facade::create_server() returns i_protocol_server
• All WebSocket tests pass
• Sample code compiles and demonstrates new interface

Technical Notes

WebSocket is connection-oriented, so adapter implementation will be simpler than UDP.

Part of #577