Add back EverythingServer for stdio

[asklar]

Adds back EverythingServer option for stdio as it is still useful.

Motivation and Context

Fixes #889

How Has This Been Tested?

locally tested both in inspector

Breaking Changes

no

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation update

Checklist

• I have read the MCP Documentation
• My code follows the repository's style guidelines
• New and existing tests pass locally
• I have added appropriate error handling
• I have added or updated documentation as needed

Additional context

[stephentoub]

@mikekistler, I think you were interested in scenarios where a single server could be used either via stdio or http? IIRC, should we do that in this one rather than having different projects?

[mikekistler]

I think both patterns are valid and it's useful to illustrate how the core MCP logic can be implemented in a class library and used in either a STDIO or sHTTP server project.

[ericstj]

In that case, can we make the STDIO server pack itself as a tool that can be run with dnx (including it's library dependency)?

[asklar]

I would like to use this server as a sample MCPB-based server. Totally up to y'all if you also want to make it available via dnx.

[ericstj]

Would that be built here? Demonstrating deployment options seems like a good thing to add to the samples, but I'll defer to @mikekistler as I'm new here.

[mikekistler]

Perhaps we should start by adding documentation on what an MCPB-based server is and why you might want one. After that we can talk about adding a sample or updating one to demonstrate that.