NwUnreachableException
Thrown by NwLoom.weave when no peer is reached within the weave timeout — the fabric never wove.
A plain Exception, deliberately not a kotlin.coroutines.cancellation.CancellationException: the earlier code rethrew the raw TimeoutCancellationException, so a caller wrapping NwLoom.weave in runCatchingCancellable saw it as its OWN structured cancellation and rethrew — an unreachable fabric masqueraded as caller cancellation. This distinct type lets callers catch a fabric failure.