feat: add a subcommand to serve a local mcp server

[ras0q]

First of all, thank you for this wonderful tool!
Currently, when using mcp-hub on its own without mcphub.nvim, you need to run mcp-hub -p <port> -c <config path> and then have MCP Clients refer to https://localhost:<port>/mcp.
I think it would be better if we could run it with mcp-hub serve -p <port> -c <config path> (or mcp-hub mcp?) using npx for a simpler execution.
Please consider this!

[joeblew999]

I also hit this .

The project feature set looks very powerful.

[pradigunara]

+1 on this, looking to use mcphub with claude code / gemini cli. maybe need some kind of stdio proxy to spawn the server + route the request just like the nvim integration