bug: OnUnregisterSession hooks not called in the StreamableHttp session termination handler

[connor-strata]

Description

When using the streamable HTTP transport, the OnUnregisterSession hooks are not called when a client terminates its session (uses the DELETE method with the session ID).

We would be happy to submit a PR for this issue. See possible solution below.

Code sample

• streamable_http.go: handleDelete

Environment

• Go version: 1.25
• mcp-go version: 0.43.1

Additional Context

Possible Solution

Call the server's UnresgisterSession method from the StreamableHTTPServer's handleDelete method:

s.server.UnregisterSession(r.Context(), sessionID)

[connor-strata]

@ezynda3 mind if I open a PR for this?

[ezynda3]

Go right ahead :)