Mixon 8 Pro display integration kit

Start with mixon-integration/PROTOCOL.md.

The macOS sender source and replay JSON files are included here.
Build: swiftc mixon-display-test.swift -o mixon-display-test
Read the protocol caveats before sending. No cold-start handshake is established.

Research article: https://tobiste.ch/blog/mixon-8-pro-display-midi.html
