Fix JS exceptions crashing the app instantly

src/screens/AdminScreen.tsx

@@ -1,4 +1,4 @@
-import React, { useState, useEffect } from 'react';
+import React, { useState, useEffect, useRef } from 'react';
 import {
   StyleSheet,
   Text,
@@ -66,6 +66,7 @@ export default function AdminScreen({ currentSettings, onSave, onClose }: AdminS
   const [printerIp, setPrinterIp] = useState<string>(currentSettings.printerIp);
   const [password, setPassword] = useState<string>(currentSettings.adminPassword);
   const [logs, setLogs] = useState<string | null>(null);
+  const scrollViewRef = useRef<ScrollView>(null);
   
   const [kioskActive, setKioskActive] = useState<boolean>(false);
   const [isDeviceOwner, setIsDeviceOwner] = useState<boolean>(false);
@@ -509,8 +510,8 @@ export default function AdminScreen({ currentSettings, onSave, onClose }: AdminS
             </View>
             <ScrollView 
               style={{ flex: 1, backgroundColor: '#000', padding: 10, borderRadius: 5 }}
-              ref={ref => { this.scrollView = ref }}
-              onContentSizeChange={() => this.scrollView?.scrollToEnd({animated: true})}
+              ref={scrollViewRef}
+              onContentSizeChange={() => scrollViewRef.current?.scrollToEnd({animated: true})}
             >
               <Text style={{ color: '#0f0', fontFamily: 'monospace' }}>{logs}</Text>
             </ScrollView>

src/screens/CameraScreen.tsx

@@ -160,7 +160,7 @@ export default function CameraScreen({
 
   // Cancel capture process
   const handleLocalCancel = () => {
-    if (countdownTimerRef.current) clearInterval(countdownTimerRef.current);
+    if (countdownTimerRef.current) clearTimeout(countdownTimerRef.current);
     if (burstTimerRef.current) clearTimeout(burstTimerRef.current);
     setCountdown(countdownDuration);
     setIsCapturing(false);