feat: scaffold ShieldAI React Native mobile app MVP (FRE-4572)

Build complete Expo/React Native mobile app with:
- Auth flow: email/password login, registration, biometric auth
- Dashboard: exposure summary, spam stats, voice protection status
- DarkWatch: watch list management, exposure feed, alert toggles
- SpamShield: call/text history, whitelist/blacklist management
- VoicePrint: family member enrollment, voice analysis
- Settings: tier management, notification preferences, security
- Push notification integration via FCM/APNs
- Offline-first state management with Zustand + AsyncStorage
- Integration with @shieldai/mobile-api-client for API services
- React Navigation with auth-aware routing (stack + bottom tabs)
- Dark theme with consistent design system (colors, spacing, typography)
- Network status monitoring and offline request queuing

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

packages/mobile/app.json

@@ -0,0 +1,66 @@
+{
+  "expo": {
+    "name": "ShieldAI",
+    "slug": "shieldai",
+    "version": "1.0.0",
+    "orientation": "portrait",
+    "icon": "./assets/icon.png",
+    "scheme": "shieldai",
+    "userInterfaceStyle": "automatic",
+    "splash": {
+      "image": "./assets/splash.png",
+      "resizeMode": "contain",
+      "backgroundColor": "#0a0e1a"
+    },
+    "ios": {
+      "supportsTablet": true,
+      "bundleIdentifier": "com.frenocorp.shieldai",
+      "infoPlist": {
+        "NSFaceIDUsageDescription": "ShieldAI uses Face ID to securely access your account.",
+        "NSCameraUsageDescription": "ShieldAI needs camera access for VoicePrint enrollment.",
+        "NSMicrophoneUsageDescription": "ShieldAI needs microphone access for voice analysis."
+      },
+      "config": {
+        "usesNonExemptEncryption": false
+      }
+    },
+    "android": {
+      "adaptiveIcon": {
+        "foregroundImage": "./assets/adaptive-icon.png",
+        "backgroundColor": "#0a0e1a"
+      },
+      "package": "com.frenocorp.shieldai",
+      "permissions": [
+        "RECEIVE_BOOT_COMPLETED",
+        "VIBRATE",
+        "android.permission.CAMERA",
+        "android.permission.RECORD_AUDIO"
+      ]
+    },
+    "web": {
+      "bundler": "metro",
+      "output": "static",
+      "favicon": "./assets/favicon.png"
+    },
+    "plugins": [
+      "expo-secure-store",
+      "expo-local-authentication",
+      [
+        "expo-notifications",
+        {
+          "icon": "./assets/notification-icon.png",
+          "color": "#4f8cff",
+          "sounds": []
+        }
+      ]
+    ],
+    "experiments": {
+      "typedRoutes": true
+    },
+    "extra": {
+      "eas": {
+        "projectId": "shieldai-project-id"
+      }
+    }
+  }
+}