* Update content according to latest spec
* Add Title to a bunch of types
* Add _meta to lots of types
* Address feedback, more cleanup, fix NAOT test failure
- It allows a single MCP session spanning multiple requests
to be handled by different servers without sharing state
- It does require the servers share data protection keys, but this
is standard for ASP.NET Core cookies and antiforgery as well
- It immediately throws for unsupported operations like sampling
