fix: use_build_context_synchronously 解消

_reanalyze で nav / messenger を async gap 前にキャプチャするよう移動。
showDialog の context 引数を ignore 対象行に統合。
dart analyze: No issues found

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

lib/screens/sake_detail_screen.dart

@@ -302,6 +302,10 @@ class _SakeDetailScreenState extends ConsumerState<SakeDetailScreen> {
  // 1. Check Locks
     if (_isAnalyzing) return;
 
+    // async gap 前に context 依存オブジェクトをキャプチャ
+    final nav = Navigator.of(context);
+    final messenger = ScaffoldMessenger.of(context);
+
  // 2. Check Quota Lockout
     final quotaLockout = ref.read(quotaLockoutProvider);
     if (quotaLockout != null) {
@@ -309,7 +313,7 @@ class _SakeDetailScreenState extends ConsumerState<SakeDetailScreen> {
       if (remaining.isNegative) {
         ref.read(quotaLockoutProvider.notifier).set(null);
       } else {
-        ScaffoldMessenger.of(context).showSnackBar(
+        messenger.showSnackBar(
           SnackBar(content: Text('AI利用制限中です。あと${remaining.inSeconds}秒お待ちください。')),
         );
         return;
@@ -326,8 +330,6 @@ class _SakeDetailScreenState extends ConsumerState<SakeDetailScreen> {
       }
     }
     if (!mounted) return;
-    final nav = Navigator.of(context);
-    final messenger = ScaffoldMessenger.of(context);
 
     if (existingPaths.isEmpty) {
       messenger.showSnackBar(
@@ -339,13 +341,8 @@ class _SakeDetailScreenState extends ConsumerState<SakeDetailScreen> {
     setState(() => _isAnalyzing = true);
 
     try {
- // ignore: use_build_context_synchronously
- // mounted チェック済み（334行目）かつ await なしで呼び出すため安全
-      showDialog(
-        context: context,
-        barrierDismissible: false,
-        builder: (context) => const AnalyzingDialog(),
-      );
+      // ignore: use_build_context_synchronously
+      showDialog(context: context, barrierDismissible: false, builder: (context) => const AnalyzingDialog());
 
       final geminiService = ref.read(geminiServiceProvider);
       final result = await geminiService.analyzeSakeLabel(existingPaths, forceRefresh: true);