The stateful GET stream and the stateless subscriptions/listen stream
capture the client address when they open and resolve every periodic
re-check with towel.WithClientIP, as the bearer middleware does, so a
failing re-check (a revoked admin token, for example) is logged with the
remote address. TestStreamRecheckClientIP records the address the verifier
sees on every verification of both streams.
Each stateless request now carries an entry-use record on its context;
getServer counts the entry it hands out as active (under the path lock)
and ServeHTTP releases it when the request ends, so a subscriptions/listen
stream keeps its entry active for its whole life. Capacity eviction walks
the LRU from the back and drops only idle entries, so it no longer ends a
quiet listener or cancels a tool call in flight, and a revocation still
finds every open stream. While every entry is busy the LRU stays above
capacity until requests end.
TestStatelessFanOut's LRU subtest now asserts that the listener's server is
spared when the binding past capacity arrives (the oldest idle server goes
instead) and that a revocation then still ends the stream.
