Low-level Server support for mcp dev and mcp run command

Currently the mcp dev and mcp run command does not support the low-level Server class. I think it's a better developer experience if we support both classes for these 2 commands, assuming there's no inherent reason for not doing so.

I'm interested in adding support for the low-level Server to both mcp dev and mcp run and I would like seek the maintainer's guidance on this. It looks like the only thing missing is the dependencies field, which is pulled from the Settings class and does not exist in the low-level Server. I'm thinking about adding a similar Settings class to server/lowlevel/server.py and thus introducing the dependencies field. The downside is more complexity in server/lowlevel/server.py which I'm not sure if it's acceptable to the maintainers and falls in line with the long term roadmap for the code base.

Please advise. Thanks.

Comienza rastreando los puntos de entrada de los comandos mcp dev y mcp run y compara cómo gestionan las clases Server de alto y bajo nivel. Lee server/lowlevel/server.py y la clase Settings existente para entender el campo dependencies que falta. Se requiere el acuerdo de los maintainers sobre el diseño y verificar la compatibilidad con Server de bajo nivel en ambos comandos para darlo por terminado.