735c837604
SessionManager called handle.agentSessionId() once at spawn and froze it in the
immutable MemberSession. For opencode that value is always null - the session
row does not exist yet when the pane is created - so fleet_list never reported
an agentSessionId and fleet_spawn{resumeSessionId} was unusable for that
backend. The handle's javadoc said 'the caller re-calls later'; no caller did,
and SessionManager did not even retain the handle.
Retain the PeerHandle per pane and re-resolve while the stored id is still
null, sticky once found, CAS-swapped into the registry.
roster() stays non-resolving - it is the roster supplier for LeadHeartbeatLoop
and FleetHealthMonitor, and resolving there would open opencode's 841MB SQLite
database on every tick, for every unresolved member, forever. rosterResolved()
carries the resolve and is used only by fleet_list and the REST roster, the two
surfaces that report the id. get(paneId) and release() resolve too, both
caller-driven.
A test pins the split: the plain roster() must never call agentSessionId()
again.