Review feedback (Enough1122): _run_cleanup -> _shutdown_agent_memory_provider
-> MemoryManager.on_session_end is session-keyed settlement (OpenViking commits
sessions/{sid} synchronously; Supermemory flushes pending turns stamped with the
session id), and at the previous head it ran AFTER the lease release — a
successor admitted during the linger could be mid-turn on the session while the
predecessor committed its remote memory session underneath.
Move the shutdown into phase 1 (after the durable flush — #88583's failure
ordering — before the finalize hook's slot in ownership). It is idempotent
(_memory_provider_shutdown), so _run_cleanup's post-release repeat is a no-op.
Also correct the docstring: phase-1 settlement is best-effort, not a proven
invariant — failures are logged and the release still happens, because an
exited process pinning the lease is worse than a dangling row (session_recovery
reaps stale rows).
Adds a discriminating test: real lease, recording agent stub, successor
acquires during the linger — memory_commit must precede release precedes
successor_acquired. Order tests now pin flush → finalize → memory → release →
linger → teardown.
(cherry picked from commit 06dc026126a473a08f182014d38f5213a842c8a3)
82c76be695