fix: address code review findings for mobile app (FRE-4572)

P0 fixes:
- Replace crypto.randomUUID() with uuid v4 (not available in RN)
- Replace Platform.Version with expo-device osVersion
- Fix auth navigation types, remove unused App route

P1 fixes:
- Push notification handler respects user preferences (useRef pattern)
- Fix stale closure: use zustand subscribe + useRef for live preferences
- Add retry logging for device registration failures
- Replace emoji tab icons with @expo/vector-icons Ionicons
- Document API integration TODOs in all local-only stores

P2 fixes:
- Add __DEV__ global declaration (global.d.ts)
- Fix package.json main field to expo/AppEntry.js
- Add retry logging for push device registration
- Add z-index/elevation to LoadingOverlay
- Add visual indicator to EmptyState icon

P3 fixes:
- Type navigation with NavigationProp<RootStackParamList>
- Move getSeverityColor to theme.ts (single source of truth)
- Add useMemo for SpamShield filter computations
- Verified usesNonExemptEncryption: false is correct for expo-secure-store

Co-Authored-By: Paperclip <noreply@paperclip.ing>

packages/mobile/src/hooks/usePushNotifications.ts

@@ -1,19 +1,30 @@
-import { useEffect, useCallback } from 'react';
+import { useEffect, useCallback, useRef } from 'react';
 import * as Notifications from 'expo-notifications';
 import { Platform } from 'react-native';
+import * as Device from 'expo-device';
 import { deviceService, notificationService } from '@shieldai/mobile-api-client';
 import { useSettingsStore } from '@/store/settingsStore';
 
-Notifications.setNotificationHandler({
-  handleNotification: async () => ({
-    shouldShowAlert: true,
-    shouldPlaySound: true,
-    shouldSetBadge: false,
-  }),
-});
-
 export function usePushNotifications() {
-  const { preferences } = useSettingsStore();
+  const preferencesRef = useRef(useSettingsStore.getState().preferences);
+
+  useEffect(() => {
+    const subscription = useSettingsStore.subscribe((state) => {
+      preferencesRef.current = state.preferences;
+    });
+    return subscription;
+  }, []);
+
+  Notifications.setNotificationHandler({
+    handleNotification: async () => {
+      const prefs = preferencesRef.current;
+      return {
+        shouldShowAlert: prefs.pushNotifications,
+        shouldPlaySound: prefs.pushNotifications,
+        shouldSetBadge: false,
+      };
+    },
+  });
 
   const registerForPushNotifications = useCallback(async () => {
     try {
@@ -33,13 +44,17 @@ export function usePushNotifications() {
         projectId: 'shieldai-project-id',
       })).data;
 
-      await deviceService.registerDevice({
-        platform: Platform.OS === 'ios' ? 'ios' : 'android',
-        pushToken: token,
-        modelName: Platform.OS === 'ios' ? 'iPhone' : 'Android',
-        osVersion: Platform.Version.toString(),
-        appVersion: '1.0.0',
-      });
+      try {
+        await deviceService.registerDevice({
+          platform: Platform.OS === 'ios' ? 'ios' : 'android',
+          pushToken: token,
+          modelName: Platform.OS === 'ios' ? 'iPhone' : 'Android',
+          osVersion: Device.osVersion || '0',
+          appVersion: '1.0.0',
+        });
+      } catch (deviceError) {
+        console.warn('Device registration failed (will retry on next launch):', deviceError);
+      }
 
       return token;
     } catch (error) {
@@ -51,7 +66,7 @@ export function usePushNotifications() {
   useEffect(() => {
     const subscription = Notifications.addNotificationReceivedListener((notification) => {
       const type = notification.request.content.data?.type;
-      const prefs = useSettingsStore.getState().preferences;
+      const prefs = preferencesRef.current;
 
       if (type === 'darkwatch_alert' && !prefs.darkwatchAlert) return;
       if (type === 'spam_blocked' && !prefs.spamBlocked) return;