* feat(session-status): implement server-authoritative session status tracking - Add server-side session states and attention tracking with Map storage - Implement SSE event broadcasting (openchamber:session-status) - Add REST API endpoints for status/attention queries - Replace client-side polling with HTTP polling + SSE push - Track needsAttention based on user message + completion + unviewed - Add MobileSessionStatusBar for mobile UI - Handle session view/unview/message-sent state transitions - Add 24h cleanup for old session states * feat(session-status): add unread indicator to mobile session status bar * refactor(session-status): extract SessionStatusHeader component Extract the session status header into a reusable component and improve layout structure in CollapsedView and ExpandedView. * feat(session-status): optimize mobile session status bar UI * refactor(session-status): remove interval polling, use snapshot sync on reconnect/visibility - unifies session status/attention sync with existing SSE lifecycle, fixes no-op store churn bug, and drops duplicated client activity state while preserving mobile unread/running UX. --------- Co-authored-by: Jovines <jovines@qq.com> Co-authored-by: Bohdan Triapitsyn <artmore@protonmail.com>