The 'auto' selection for the previous tag has been working well. And this also fixes a typo.

- 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

- Add missing filling of ResourceCollection in McpServerOptionsSetup
- Remove AIFunctionMcpServerXx.ToString overrides; for resources, it was changing behavior undesirably, and for the others it was duplicate code.
- Fix notification method used for resource list changes.
- Fix type in WithResources parameter name.

* Improve exception diagnostics for stdio client

Track the last several lines of stderr and include those in an exception created as part of CleanupAsync if the server process has already exited. This is based on an assumption that the server should never exit prior to CleanupAsync being called.

* Address feedback and fix test failure

No meaningful code changes, just lots of namespace shuffling to have fewer namespaces and to put things in better namespaces.