Summary

Enhances websocket thread shutdown to prevent indefinite hangs and improve error handling during server shutdown. Adds timeout protection, non-blocking I/O configuration, and comprehensive error handling to ensure graceful and predictable shutdown behavior.

Problem

During server shutdown, the websocket thread cleanup could hang indefinitely when attempting to send close frames to unresponsive clients. This was caused by:

1. No timeout protection - blocked indefinitely on slow/dead connections
2. Blocking I/O - send() operations could block the shutdown process
3. No error handling - syscall failures were silently ignored
4. Poor visibility - no logging of shutdown progress or issues

This could delay or prevent clean server shutdown, especially under high load or network issues.