Defer and coalesce global catalogue refreshes while SessionDetail is active, carry session metadata through incremental patches, and gate in-flight catalogue commits by route. Harden the virtual timeline cold-open and user-scroll lifecycle, and add Electron frame, continuity, metadata, and overlap regressions.
Track real user scrolling through scrollend with a quiet watchdog, defer timeline commits and virtualizer corrections until settlement, and make SessionDetail the sole tail-follow owner. Add unit and Electron regressions for scroll writes, reader anchoring, near-tail escape, explicit navigation, and flap timing.
tommy0103