feat(mobile): KI-AGENT: Föderierte Chats und gemeinsame Sichtbarkeit ergänzen

mobile/app/(tabs)/_layout.tsx

@@ -1,12 +1,13 @@
 import * as Notifications from 'expo-notifications';
 import { Redirect, Tabs } from 'expo-router';
-import { useCallback, useEffect, useMemo, useState } from 'react';
+import { useEffect, useMemo, useState } from 'react';
+import { AppState, DeviceEventEmitter } from 'react-native';
 
 import { HapticTab } from '@/components/haptic-tab';
 import { IconSymbol } from '@/components/ui/icon-symbol';
 import { Colors } from '@/constants/theme';
 import { useColorScheme } from '@/hooks/use-color-scheme';
-import { fetchChatUnreadCounts } from '@/src/lib/api';
+import { chatApi } from '@/src/lib/chat-api';
 import { useAuth } from '@/src/providers/auth-provider';
 
 export default function TabLayout() {
@@ -14,31 +15,27 @@ export default function TabLayout() {
   const { activeTenantId, isBootstrapping, token, requiresTenantSelection } = useAuth();
   const [communicationUnread, setCommunicationUnread] = useState(0);
 
-  const refreshCommunicationUnread = useCallback(async () => {
-    if (!token || requiresTenantSelection) {
-      setCommunicationUnread(0);
-      await Notifications.setBadgeCountAsync(0);
-      return;
-    }
-
-    try {
-      const unread = await fetchChatUnreadCounts(token);
-      const total = Object.values(unread).reduce((sum, room) => sum + (room.count || 0), 0);
-      setCommunicationUnread(total);
-      await Notifications.setBadgeCountAsync(total);
-    } catch {
-      // Badge loading must not block tab navigation.
-    }
-  }, [requiresTenantSelection, token]);
-
   useEffect(() => {
-    void refreshCommunicationUnread();
-
-    if (!token || requiresTenantSelection) return undefined;
-
-    const id = setInterval(() => void refreshCommunicationUnread(), 30000);
-    return () => clearInterval(id);
-  }, [activeTenantId, refreshCommunicationUnread, requiresTenantSelection, token]);
+    let active = true;
+    let revision = 0;
+    setCommunicationUnread(0);
+    void Notifications.setBadgeCountAsync(0).catch(() => undefined);
+    async function refresh() {
+      if (!token || !activeTenantId || requiresTenantSelection || AppState.currentState !== 'active') return;
+      const request = ++revision;
+      try {
+        const total = await chatApi.unread(token);
+        if (!active || request !== revision) return;
+        setCommunicationUnread(total);
+        await Notifications.setBadgeCountAsync(total);
+      } catch { /* Badge loading must not block tab navigation. */ }
+    }
+    void refresh();
+    const timer = setInterval(() => void refresh(), 30000);
+    const foreground = AppState.addEventListener('change', state => { if (state === 'active') void refresh(); });
+    const changed = DeviceEventEmitter.addListener('fedeo:chat-changed', () => void refresh());
+    return () => { active = false; ++revision; clearInterval(timer); foreground.remove(); changed.remove(); };
+  }, [activeTenantId, requiresTenantSelection, token]);
 
   const communicationBadge = useMemo(() => {
     if (!communicationUnread) return undefined;