fix(ad): 스크린샷 모드에서 네이티브 광고 비활성화

lib/presentation/widgets/native_ad_placeholder.dart

@@ -13,12 +13,14 @@ class NativeAdPlaceholder extends StatefulWidget {
   final EdgeInsetsGeometry? margin;
   final double height;
   final Duration refreshInterval;
+  final bool enabled;
 
   const NativeAdPlaceholder({
     super.key,
     this.margin,
     this.height = 200,
     this.refreshInterval = const Duration(minutes: 2),
+    this.enabled = true,
   });
 
   @override
@@ -35,7 +37,7 @@ class _NativeAdPlaceholderState extends State<NativeAdPlaceholder> {
   void initState() {
     super.initState();
     WidgetsBinding.instance.addPostFrameCallback((_) {
-      if (!mounted) return;
+      if (!mounted || !widget.enabled) return;
       _loadAd();
     });
   }
@@ -43,6 +45,20 @@ class _NativeAdPlaceholderState extends State<NativeAdPlaceholder> {
   @override
   void didUpdateWidget(covariant NativeAdPlaceholder oldWidget) {
     super.didUpdateWidget(oldWidget);
+    if (!widget.enabled) {
+      _disposeAd();
+      setState(() {
+        _isLoading = false;
+        _isLoaded = false;
+      });
+      return;
+    }
+
+    if (!oldWidget.enabled && widget.enabled) {
+      _loadAd();
+      return;
+    }
+
     if (widget.refreshInterval != oldWidget.refreshInterval && _isLoaded) {
       _scheduleRefresh();
     }
@@ -50,12 +66,19 @@ class _NativeAdPlaceholderState extends State<NativeAdPlaceholder> {
 
   @override
   void dispose() {
-    _refreshTimer?.cancel();
-    _nativeAd?.dispose();
+    _disposeAd();
     super.dispose();
   }
 
+  void _disposeAd() {
+    _refreshTimer?.cancel();
+    _refreshTimer = null;
+    _nativeAd?.dispose();
+    _nativeAd = null;
+  }
+
   void _loadAd() {
+    if (!widget.enabled) return;
     if (!AdHelper.isMobilePlatform) return;
     if (!mounted) return;
 
@@ -102,6 +125,7 @@ class _NativeAdPlaceholderState extends State<NativeAdPlaceholder> {
   void _scheduleRefresh({bool retry = false}) {
     _refreshTimer?.cancel();
     if (!mounted) return;
+    if (!widget.enabled) return;
     final delay = retry ? const Duration(seconds: 30) : widget.refreshInterval;
     _refreshTimer = Timer(delay, _loadAd);
   }
@@ -132,7 +156,7 @@ class _NativeAdPlaceholderState extends State<NativeAdPlaceholder> {
   Widget build(BuildContext context) {
     final isDark = Theme.of(context).brightness == Brightness.dark;
 
-    if (!AdHelper.isMobilePlatform) {
+    if (!AdHelper.isMobilePlatform || !widget.enabled) {
       return _buildPlaceholder(isDark, isLoading: false);
     }