feat: add frontend Rich Presence — activityStore, ActivityCard, sidebar upgrades, settings toggle

- Task 7: Create activityStore (Zustand) with Map<userId, Activity[]>, showActivity toggle,
  debounced pushActivities, and reset on logout
- Task 8: Wire WS integration — presence_update propagates activities to store,
  ready payload initializes userActivities and showActivity (via setState to avoid side effects)
- Task 9: Create ActivityCard component with compact/full modes, type-colored labels,
  elapsed time display, asset images, and fallback to customStatus
- Task 10: Upgrade ActivityPanel to three groups — active friends (full cards, no header),
  online friends (compact), offline friends — using getPrimaryActivity for grouping
- Task 11: Upgrade MemberSidebar to show compact ActivityCards instead of raw customStatus
- Task 12: Add showActivity toggle in AccountPanel settings (Activity Status section)
  with API persistence and store sync

packages/web/src/stores/authStore.ts

@@ -6,6 +6,7 @@ import { useSpaceStore } from './spaceStore';
 import { useSocialStore } from './socialStore';
 import { useVoiceStore } from './voiceStore';
 import { useInstanceStore } from './instanceStore';
+import { useActivityStore } from './activityStore';
 import { syncProfileUpdateToRemotes } from '../utils/profileSync';
 import { changePasswordOnRemotes, deleteAccountOnRemotes, type FederationOpResult } from '../utils/federationOps';
 import { clearSelfIds } from '../utils/identity';
@@ -35,6 +36,7 @@ function resetUserStores() {
   useSocialStore.getState().reset();
   useVoiceStore.getState().resetSession();
   useInstanceStore.getState().reset();
+  useActivityStore.getState().reset();
 }
 
 export const useAuthStore = create<AuthState>((set, get) => ({