Chat (lite)

Server push over SSE: posting goes through a server function; the broadcast comes back on the chat push channel — open a second tab to see it.

• pushSubscribe("chat", …) delivers every SSE frame to a chunk export
• the server's publisher thread drains new messages 5×/second
• sending reads the input with refValueStr and POSTs postChat
• messages render into a ring of six bound slots

Guide: Server functions