mcp web improvements

Hi, Fatih.

Awesome work and thanks for that, mcp is strange standard that should be perceived as black box, but you actually giving a little bit of light into it.

Couple suggestions, that you may consider:
1. It would be great if mcp web would open a page instantly, when server is up. Like with: https://www.npmjs.com/package/open
2. When you are launching two mcp web commands you will have a port conflict. But you shouldn't care about a port, so probably if default is bind, search for another one, like: https://www.npmjs.com/package/portfinder

p.s. I do know that repo is written in go, so nom links is just for the reference