Sync changes brought by MegrezNT 1.2.2-1.2.4.

[ShikiSuen]

• Introducing LanguageModelProtocol.
• MegrezNT (written in C#) has been thoroughly inspected and optimized by IntelliJ Rider. This process brought some optimizations to the codebase structure(*), and I manually migrated them to this original Swift version.

(*) Too bad that their AppCode just crashes / freezes like a fuck almost every time performing solution-wide inspection and later only complaints about what it thinks of "typos". Totally useless piece of shit. If you have that money, buy their Rider instead -- World-class best C# IDE, period.