fix: move CameraScreen off-screen when not active so TextureView doesn't cover UI

App.tsx

@@ -147,7 +147,13 @@ export default function App() {
           Keep CameraScreen ALWAYS mounted in the background to prevent 
           Android expo-camera hardware crashes when unmounting right after capture 
         */}
-        <View style={StyleSheet.absoluteFill}>
+        <View 
+          style={[
+            StyleSheet.absoluteFill, 
+            currentScreen !== 'camera' && { opacity: 0, zIndex: -10, transform: [{ translateX: -10000 }] }
+          ]} 
+          pointerEvents={currentScreen === 'camera' ? 'auto' : 'none'}
+        >
           <CameraScreen
             countdownDuration={settings.countdownDuration}
             onPhotoCaptured={handlePhotoCaptured}
@@ -169,7 +175,7 @@ export default function App() {
 
         {/* Overlay PreviewScreen if active */}
         {currentScreen === 'preview' && (
-          <View style={StyleSheet.absoluteFill}>
+          <View style={[StyleSheet.absoluteFill, { zIndex: 100, elevation: 100, backgroundColor: '#000' }]}>
             <PreviewScreen
               photoUris={photoUris}
               printerIp={settings.printerIp}
@@ -188,7 +194,7 @@ export default function App() {
 
         {/* Overlay AdminScreen if active */}
         {currentScreen === 'admin' && (
-          <View style={StyleSheet.absoluteFill}>
+          <View style={[StyleSheet.absoluteFill, { zIndex: 100, elevation: 100, backgroundColor: '#000' }]}>
             <AdminScreen
               currentSettings={settings}
               onSave={handleSaveSettings}