- reconcile_once only walked desired=on streams, so a token left "releasing"
by /leave while its node was offline (or a deleted node) never returned to
the pool until that node came back (server-26#204 leak shape). Sweep leased
tokens whose node is offline/deleted past the lease grace.
- publish_desired stamped release_seq AFTER building the list, so a stop
landing between the two got a seq whose list still held the stream; an ack
for it could free a token the node was still told to use. Stamp first.
Three regression tests; each fails on the previous commit.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>