Allow tools to continue running when session is closed

Is your feature request related to a problem? Please describe.

A server may implement a long-running tool that should continue running if the client disconnects or session is closed due to idle timeout.

The MCP Spec permits this case and has provisions for reconnecting to the server to resume its connection to the tool (resumable streams), but this is currently not possible with the C# SDK because it terminates tool calls when the session is closed.

Describe the solution you'd like

An option in the McpServerOptions, or maybe in the HttpTransport options, or maybe on individual tools, that skip cancellation of outstanding tool calls when a session is closed.

Describe alternatives you've considered

An alternative might be to not close a session when the client disconnects, and/or disable the idle session timeout.

Inizia tracciando il modo in cui la chiusura della sessione e i timeout di inattività annullano le chiamate agli strumenti in sospeso nel C# SDK. Confronta McpServerOptions, le opzioni di HttpTransport e la configurazione dei singoli strumenti con le disposizioni di MCP sui flussi riprendibili. Il lavoro è completato quando un’opzione documentata conserva le chiamate agli strumenti idonee dopo una disconnessione o la chiusura della sessione e supporta la riconnessione a esse.