Fix camera unmount crash via overlay architecture

App.tsx

@@ -81,24 +81,36 @@ export default function App() {
   };
 
   // 3. Conditional Screen Rendering
-  const renderScreen = () => {
-    switch (currentScreen) {
-      case 'camera':
   return (
+    <GestureHandlerRootView style={styles.container}>
+      <SafeAreaView style={styles.container}>
+        <StatusBar hidden={true} />
+        
+        {/* 
+          Keep CameraScreen ALWAYS mounted in the background to prevent 
+          Android expo-camera hardware crashes when unmounting right after capture 
+        */}
+        <View style={StyleSheet.absoluteFill}>
           <CameraScreen
             countdownDuration={settings.countdownDuration}
             onPhotoCaptured={handlePhotoCaptured}
             onBurstComplete={handleBurstComplete}
             onCancel={handleReset}
-            isIdle={false}
+            isIdle={currentScreen === 'home'}
+            onStartBooth={handleStartBooth}
+            onNavigateToAdmin={handleOpenAdmin}
+            adminPassword={settings.adminPassword}
+            welcomeText={settings.welcomeText}
             burstCount={settings.burstCount}
             burstIntervalSec={settings.burstIntervalSec}
             frameMode={settings.frameMode}
             selectedFrameId={settings.selectedFrameId}
           />
-        );
+        </View>
-      case 'preview':
+
-        return (
+        {/* Overlay PreviewScreen if active */}
+        {currentScreen === 'preview' && (
+          <View style={StyleSheet.absoluteFill}>
             <PreviewScreen
               photoUris={photoUris}
               printerIp={settings.printerIp}
@@ -112,41 +124,19 @@ export default function App() {
               dateOverlayPosition={settings.dateOverlayPosition}
               eventText={settings.eventText}
             />
-        );
+          </View>
-      case 'admin':
+        )}
-        return (
+
+        {/* Overlay AdminScreen if active */}
+        {currentScreen === 'admin' && (
+          <View style={StyleSheet.absoluteFill}>
             <AdminScreen
               currentSettings={settings}
               onSave={handleSaveSettings}
               onClose={() => setCurrentScreen('home')}
             />
-        );
+          </View>
-      default:
+        )}
-        return (
-          <CameraScreen
-            countdownDuration={settings.countdownDuration}
-            onPhotoCaptured={handlePhotoCaptured}
-            onBurstComplete={handleBurstComplete}
-            onCancel={handleReset}
-            isIdle={true}
-            onStartBooth={handleStartBooth}
-            onNavigateToAdmin={handleOpenAdmin}
-            adminPassword={settings.adminPassword}
-            welcomeText={settings.welcomeText}
-            burstCount={settings.burstCount}
-            burstIntervalSec={settings.burstIntervalSec}
-            frameMode={settings.frameMode}
-            selectedFrameId={settings.selectedFrameId}
-          />
-        );
-    }
-  };
-
-  return (
-    <GestureHandlerRootView style={styles.container}>
-      <SafeAreaView style={styles.container}>
-        <StatusBar hidden={true} />
-        {renderScreen()}
       </SafeAreaView>
     </GestureHandlerRootView>
   );