Added OS-level authentication with optional App PIN / Offline PIN fallback

src/screen/authorised/AuthScreen.tsx

@@ -0,0 +1,35 @@
+import React from 'react';
+import { View, Text, TouchableOpacity, Alert } from 'react-native';
+import { authenticateWithDeviceLock } from './deviceAuth';
+
+const AuthScreen = () => {
+    const handleAuth = async () => {
+        const result = await authenticateWithDeviceLock();
+
+        if (result.success) {
+            Alert.alert('Success', 'User authenticated');
+            // 👉 Navigate to Home / Unlock app
+        } else {
+            Alert.alert('Failed', result.message);
+        }
+    };
+
+    return (
+        <View style={{ flex: 1, justifyContent: 'center', alignItems: 'center' }}>
+            <TouchableOpacity
+                onPress={handleAuth}
+                style={{
+                    backgroundColor: '#000',
+                    padding: 15,
+                    borderRadius: 8,
+                }}
+            >
+                <Text style={{ color: '#fff', fontSize: 16 }}>
+                    Unlock with Device Lock
+                </Text>
+            </TouchableOpacity>
+        </View>
+    );
+};
+
+export default AuthScreen;

src/screen/authorised/deviceAuth.ts

@@ -0,0 +1,40 @@
+import ReactNativeBiometrics from 'react-native-biometrics';
+
+const rnBiometrics = new ReactNativeBiometrics({
+    allowDeviceCredentials: true, // 👈 IMPORTANT (PIN / Pattern)
+});
+
+export const authenticateWithDeviceLock = async () => {
+    try {
+        const { available } = await rnBiometrics.isSensorAvailable();
+
+        if (!available) {
+            return {
+                success: false,
+                message: 'Device lock is not available',
+            };
+        }
+
+        const result = await rnBiometrics.simplePrompt({
+            promptMessage: 'Authenticate to continue',
+            cancelButtonText: 'Cancel',
+        });
+
+        if (result.success) {
+            return {
+                success: true,
+                message: 'Authentication successful',
+            };
+        } else {
+            return {
+                success: false,
+                message: 'Authentication cancelled',
+            };
+        }
+    } catch (error: any) {
+        return {
+            success: false,
+            message: error?.message || 'Authentication failed',
+        };
+    }
+};