Track readable content revisions and durable read cursors in the hub. Acknowledge only rendered foreground tails, persist offline read operations, and preserve newer manual unread choices across devices.
Migrate existing history to a read baseline and cover pagination receipts with shared native conformance fixtures.
Persist and backfill the last user-message timestamp, and use it for deterministic session ordering across web and native clients while preserving manual pins.
Remove the fixed-order setting and guard ordering against transcript echoes, replayed messages, and stale REST/SSE updates. Add regression coverage and regenerate the SSE fixture.
weishu