feat(session-status): mobile session quick switch with running/unread indicators (#340)

* 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>

packages/ui/src/stores/sessionStore.ts

@@ -8,6 +8,7 @@ import { getWorktreeStatus } from "@/lib/worktrees/worktreeStatus";
 import { listProjectWorktrees, removeProjectWorktree } from "@/lib/worktrees/worktreeManager";
 import { useDirectoryStore } from "./useDirectoryStore";
 import { useProjectsStore } from "./useProjectsStore";
+import { triggerSessionStatusPoll } from "@/hooks/useServerSessionStatus";
 import type { ProjectEntry } from "@/lib/api/types";
 import { checkIsGitRepository } from "@/lib/gitApi";
 import { streamDebugEnabled } from "@/stores/utils/streamDebug";
@@ -1237,7 +1238,26 @@ export const useSessionStore = create<SessionStore>()(
                 },
 
                 setCurrentSession: (id: string | null) => {
+                    const prevSessionId = get().currentSessionId;
                     set({ currentSessionId: id, error: null });
+
+                    // Notify server of view state changes
+                    // This enables server-side needs_attention tracking
+                    if (prevSessionId && prevSessionId !== id) {
+                        // Leaving previous session
+                        fetch(`/api/sessions/${prevSessionId}/unview`, { method: 'POST' })
+                            .catch(() => { /* ignore */ });
+                    }
+                    if (id) {
+                        // Entering new session
+                        fetch(`/api/sessions/${id}/view`, { method: 'POST' })
+                            .catch(() => { /* ignore */ });
+                    }
+
+                    // Trigger immediate poll to get latest attention states
+                    // This prevents stale state when switching sessions
+                    triggerSessionStatusPoll();
+
                     const directory = opencodeClient.getDirectory() ?? null;
                     storeSessionForDirectory(directory, id);
                 },
@@ -1513,7 +1533,7 @@ export const useSessionStore = create<SessionStore>()(
 
         const mergedSessions = dedupeSessionsById(persistedSessions);
 
-        return {
+        const mergedResult = {
             ...currentState,
             ...persistedState,
             sessions: mergedSessions,
@@ -1527,6 +1547,7 @@ export const useSessionStore = create<SessionStore>()(
                 : currentState.availableWorktreesByProject,
             lastLoadedDirectory,
         };
+        return mergedResult;
     },
             }
         ),