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/store/spamShieldStore.ts

@@ -3,6 +3,11 @@ import { persist, createJSONStorage } from 'zustand/middleware';
 import AsyncStorage from '@react-native-async-storage/async-storage';
 import type { SpamRecord } from '@/types';
 
+/**
+ * TODO: Wire store operations to @shieldai/mobile-api-client for production.
+ * Current implementation is local-only (AsyncStorage) for offline-first MVP.
+ */
+
 type PhoneList = { number: string; label: string }[];
 
 interface SpamShieldState {