transports: a close that times out must be distinguishable from a confirmed close #774

WsNoiseTransport.close() (packages/cli/src/utils/ws-noise-transport.ts ~:124) and the Noise IK transport's close() (noise-ik-transport.ts ~:163) resolve when the socket's close event fires, and also after a 2 s safety timeout. A close handshake that stalls therefore resolves exactly like a confirmed close. Callers such as the relay's retry path and stop() cannot tell a stalled close from a closed channel, so they report and clean up as if the channel were gone.

What the fix does: a transport close reports whether the close was confirmed. For example, it resolves to a result that distinguishes closed from timed-out, or rejects on the timeout with a named error. Callers that act on a close (the relay's attempt cleanup and stop(), office kill) treat an unconfirmed close as a failure: they report it, keep any record that depends on the channel being gone, and exit non-zero where they already do for other close failures. A real local WebSocket test stalls the peer's close and asserts the unconfirmed result and the caller's failure path.

Refs #748, #759.