* Close SSH connections still in the handshake on Stop and reject ones accepted by a stopped server
* Add a test that a connection dialed after Stop is refused
* [client] Clarify SSH server lifecycle and connection validation comments
* Clarify trackConn's doc comment on connection ownership after rejection
* Stop asserting a specific outcome of the Stop/Serve registration race in the post-Stop dial test
* Explicitly close the SSH listener on Stop and avoid logging the resulting race as an error
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Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>