Accept registered WebSocket close codes

[OskarEichler]

Add registered close codes 1012, 1013, and 1014. Incoming frames using these IANA-registered values are currently rewritten to protocol error 1002. The full 196-example suite passes on Ruby 4.0.6 and Ruby 3.2.11, as do the cumulative protocol model and native builds.

[jcoglan]

I mentioned in faye/websocket-extensions-ruby#8 that the Faye project does not accept LLM-authored code. Since all these PRs and the commits they contain were created at the same time, I would suspect they are created by an agent. Have you used any LLM agents or other automation in the production of these PRs?

If the code is your own work, then these PRs would all need unit tests adding to cover their changes, and I'd appreciate if you could check your work using https://github.com/faye/wstest.

[OskarEichler]

Yes—these changes were produced with assistance from an LLM agent. I respect the project policy you shared, so I’m closing this PR and the other open Faye PRs from this batch. Sorry for the noise.