Parent Issue

Part of #315 (TCP receive std::span callback migration)

Summary

Migrate WebSocket receive flow to use tcp_socket's std::span<const uint8_t> callback so WebSocket receive does not require per-TCP-read std::vector construction just to hand off bytes to the protocol layer.

Background

websocket_socket currently registers a vector-based receive callback:

• tcp_socket_->set_receive_callback([...] (const std::vector<uint8_t>& data) { on_tcp_receive(data); }) (src/internal/websocket_socket.cpp:72)

websocket_protocol::process_data() also currently takes const std::vector<uint8_t>& (include/kcenon/network/internal/websocket_protocol.h:127).

With the new span callback in tcp_socket (#316), WebSocket should consume bytes as a view and let the protocol layer append into its internal buffer, avoiding an intermediate vector allocation on every read.

Proposed Solution

1) Update websocket_protocol API to accept a view

Change:

• websocket_protocol::process_data(const std::vector<uint8_t>&)
  To:
• websocket_protocol::process_data(std::span<const uint8_t>)

Implementation: append incoming bytes into buffer_ (already a std::vector<uint8_t>), then parse frames as today.

2) Update websocket_socket to register span callback

• Use tcp_socket_->set_receive_callback_view(...)
• Update websocket_socket::on_tcp_receive to accept std::span<const uint8_t> and forward to protocol_.process_data(span).

3) Update tests and docs

• Update tests/unit/websocket_protocol_test.cpp call sites for the new signature
• Update any docs/examples referencing process_data(vector) (e.g. docs/FEATURES_KO.md)

Files to Update

• include/kcenon/network/internal/websocket_protocol.h
• src/internal/websocket_protocol.cpp
• include/kcenon/network/internal/websocket_socket.h
• src/internal/websocket_socket.cpp
• tests/unit/websocket_protocol_test.cpp
• Docs as needed (search for process_data( usage)

Acceptance Criteria

• WebSocket receive path uses tcp_socket span callback
• websocket_protocol::process_data accepts std::span<const uint8_t>
• No per-read std::vector is required solely to adapt TCP bytes into the protocol layer
• Unit tests pass (websocket_protocol_test and any WebSocket integration tests)

Test Plan

• Run:
  • ctest --output-on-failure -R websocket
  • ctest --output-on-failure (full suite as time permits)