feat: Redesign Lite version Pro-lock UX with crown badge and dialog

## UI/UX Improvements (User Feedback Implementation)
- Add crown badge to Pro-locked tab icons (Instagram, Analytics, Scan)
- Replace full-screen ProLockedScreen with compact AlertDialog
- Prevent tab navigation to locked features (show dialog instead)
- Follows industry standards (Spotify, Notion, Canva pattern)

## User Experience Benefits
1. Clear visual indicator (crown badge) BEFORE tapping
2. Lightweight dialog instead of full-screen transition
3. No page navigation = smoother, less frustrating experience
4. Reduced "disappointment factor" through expectation management

## Technical Changes
- Added `_IconWithCrownBadge` widget for tab icons
- Added `_showProOnlyDialog()` method for Pro-only feature alerts
- Modified `onDestinationSelected` to intercept locked tab taps
- Simplified screens list (locked tabs show HomeScreen dummy)

## Build Optimization
- Release APK size: 47.1MB (Lite) / 47.2MB (Pro)
- Both versions optimized with tree-shaking and R8
- Single architecture (arm64) for optimal size

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

lib/screens/main_screen.dart

@@ -5,12 +5,44 @@ import '../main.dart'; // Import isProVersion flag
 import '../providers/theme_provider.dart'; // Access userProfileProvider
 import '../providers/navigation_provider.dart'; // Track current tab index
 import '../utils/translations.dart'; // Translation helper
-import '../widgets/pro_locked_screen.dart'; // Pro版ロック画面
 import 'home_screen.dart';
 import 'soul_screen.dart';
 import 'shop_settings_screen.dart';
 import 'placeholders/placeholders.dart';
 
+/// 王冠バッジ付きアイコンウィジェット（Pro限定機能用）
+class _IconWithCrownBadge extends StatelessWidget {
+  final IconData icon;
+
+  const _IconWithCrownBadge({required this.icon});
+
+  @override
+  Widget build(BuildContext context) {
+    return Stack(
+      clipBehavior: Clip.none,
+      children: [
+        Icon(icon),
+        Positioned(
+          right: -4,
+          top: -4,
+          child: Container(
+            padding: const EdgeInsets.all(2),
+            decoration: BoxDecoration(
+              color: Colors.amber.shade600,
+              shape: BoxShape.circle,
+            ),
+            child: const Icon(
+              LucideIcons.crown,
+              size: 10,
+              color: Colors.white,
+            ),
+          ),
+        ),
+      ],
+    );
+  }
+}
+
 class MainScreen extends ConsumerStatefulWidget {
   const MainScreen({super.key});
 
@@ -21,6 +53,56 @@ class MainScreen extends ConsumerStatefulWidget {
 class _MainScreenState extends ConsumerState<MainScreen> {
   int _currentIndex = 0;
 
+  /// Pro限定機能ダイアログを表示
+  void _showProOnlyDialog(BuildContext context, String featureName, IconData featureIcon, String description) {
+    showDialog(
+      context: context,
+      builder: (context) => AlertDialog(
+        icon: Stack(
+          clipBehavior: Clip.none,
+          alignment: Alignment.center,
+          children: [
+            Icon(featureIcon, size: 48, color: Colors.grey.shade400),
+            Positioned(
+              right: -8,
+              top: -8,
+              child: Icon(LucideIcons.crown, size: 32, color: Colors.amber.shade600),
+            ),
+          ],
+        ),
+        title: const Text('Pro版限定機能', textAlign: TextAlign.center),
+        content: Column(
+          mainAxisSize: MainAxisSize.min,
+          children: [
+            Text(
+              featureName,
+              style: const TextStyle(fontSize: 18, fontWeight: FontWeight.w600),
+              textAlign: TextAlign.center,
+            ),
+            const SizedBox(height: 12),
+            Text(
+              description,
+              style: TextStyle(fontSize: 14, color: Colors.grey.shade700),
+              textAlign: TextAlign.center,
+            ),
+            const SizedBox(height: 16),
+            Text(
+              'Ponshu Room Pro版でこの機能をご利用いただけます。',
+              style: TextStyle(fontSize: 12, color: Colors.grey.shade600),
+              textAlign: TextAlign.center,
+            ),
+          ],
+        ),
+        actions: [
+          TextButton(
+            onPressed: () => Navigator.of(context).pop(),
+            child: const Text('閉じる'),
+          ),
+        ],
+      ),
+    );
+  }
+
   @override
   Widget build(BuildContext context) {
     // Listen for mode changes to reset navigation to Home
@@ -50,58 +132,39 @@ class _MainScreenState extends ConsumerState<MainScreen> {
     debugPrint('🔍 MainScreen: IS_PRO_VERSION = $isProVersion, isBusiness = $isBusiness');
 
     // Define Screens for each mode
-    // Pro版かLite版かで画面を切り替え
+    // Lite版のPro限定タブは表示されないようにダミー画面を配置
+    // （タップ時にダイアログで対応するため、画面遷移は発生しない）
     final List<Widget> screens = isBusiness
         ? [
-            const HomeScreen(), // Inventory Management (FAB opens Menu Creation)
+            const HomeScreen(), // Inventory Management
-            // Instagram Support: Pro版のみ
+            isProVersion ? const InstaSupportScreen() : const HomeScreen(), // Instagram Support (Pro only)
-            isProVersion
+            isProVersion ? const AnalyticsScreen() : const HomeScreen(), // Analytics (Pro only)
-                ? const InstaSupportScreen()
-                : ProLockedScreen(
-                    featureName: t['promo'],
-                    featureIcon: LucideIcons.instagram,
-                    description: userProfile.locale == 'ja'
-                        ? 'Instagram用の魅力的な投稿を自動生成。\n酒の写真とAI解析を活用して、\nプロモーションをサポートします。'
-                        : 'Auto-generate attractive Instagram posts.\nLeverage sake photos and AI analysis\nto boost your promotion.',
-                  ),
-            // Analytics: Pro版のみ
-            isProVersion
-                ? const AnalyticsScreen()
-                : ProLockedScreen(
-                    featureName: t['analytics'],
-                    featureIcon: LucideIcons.barChart,
-                    description: userProfile.locale == 'ja'
-                        ? '在庫状況や人気銘柄を分析。\nビジネスの意思決定を\nデータで支援します。'
-                        : 'Analyze inventory and popular brands.\nSupport business decisions\nwith data insights.',
-                  ),
             const ShopSettingsScreen(), // Shop Settings
           ]
         : [
             const HomeScreen(), // My Sake List
-            // QR Scan: Pro版のみ
+            isProVersion ? const ScanARScreen() : const HomeScreen(), // QR Scan (Pro only)
-            isProVersion
+            const SommelierScreen(), // Sommelier
-                ? const ScanARScreen()
+            const BreweryMapScreen(), // Map
-                : ProLockedScreen(
-                    featureName: t['scan'],
-                    featureIcon: LucideIcons.scanLine,
-                    description: userProfile.locale == 'ja'
-                        ? 'QRコードをスキャンして、\n酒の情報を素早く登録。\nAR表示で楽しく記録できます。'
-                        : 'Scan QR codes to quickly register\nsake information.\nEnjoy recording with AR display.',
-                  ),
-            const SommelierScreen(),
-            const BreweryMapScreen(),
             const SoulScreen(), // MyPage/Settings
           ];
 
     // Define Navigation Items (with translation)
+    // Lite版では王冠バッジを表示
     final List<NavigationDestination> destinations = isBusiness
         ? [
             NavigationDestination(
                icon: const Padding(padding: EdgeInsets.only(bottom: 2), child: Text('🍶', style: TextStyle(fontSize: 22))),
                label: t['home'],
             ),
-            NavigationDestination(icon: const Icon(LucideIcons.instagram), label: t['promo']),
+            NavigationDestination(
-            NavigationDestination(icon: const Icon(LucideIcons.barChart), label: t['analytics']),
+              icon: isProVersion ? const Icon(LucideIcons.instagram) : const _IconWithCrownBadge(icon: LucideIcons.instagram),
+              label: t['promo'],
+            ),
+            NavigationDestination(
+              icon: isProVersion ? const Icon(LucideIcons.barChart) : const _IconWithCrownBadge(icon: LucideIcons.barChart),
+              label: t['analytics'],
+            ),
             NavigationDestination(icon: const Icon(LucideIcons.store), label: t['shop']),
           ]
         : [
@@ -109,7 +172,10 @@ class _MainScreenState extends ConsumerState<MainScreen> {
               icon: const Padding(padding: EdgeInsets.only(bottom: 2), child: Text('🍶', style: TextStyle(fontSize: 22))),
               label: t['home'],
             ),
-            NavigationDestination(icon: const Icon(LucideIcons.scanLine), label: t['scan']),
+            NavigationDestination(
+              icon: isProVersion ? const Icon(LucideIcons.scanLine) : const _IconWithCrownBadge(icon: LucideIcons.scanLine),
+              label: t['scan'],
+            ),
             NavigationDestination(icon: const Icon(LucideIcons.sparkles), label: t['sommelier']),
             NavigationDestination(icon: const Icon(LucideIcons.map), label: t['map']),
             NavigationDestination(icon: const Icon(LucideIcons.user), label: t['myPage']),
@@ -128,6 +194,48 @@ class _MainScreenState extends ConsumerState<MainScreen> {
       bottomNavigationBar: NavigationBar(
         selectedIndex: _currentIndex,
         onDestinationSelected: (index) {
+          // Lite版でPro限定タブをタップした場合はダイアログを表示
+          if (!isProVersion) {
+            if (isBusiness) {
+              // ビジネスモード: Instagram (index 1) と Analytics (index 2) がPro限定
+              if (index == 1) {
+                _showProOnlyDialog(
+                  context,
+                  t['promo'],
+                  LucideIcons.instagram,
+                  userProfile.locale == 'ja'
+                      ? 'Instagram用の魅力的な投稿を自動生成。酒の写真とAI解析を活用して、プロモーションをサポートします。'
+                      : 'Auto-generate attractive Instagram posts. Leverage sake photos and AI analysis to boost your promotion.',
+                );
+                return;
+              } else if (index == 2) {
+                _showProOnlyDialog(
+                  context,
+                  t['analytics'],
+                  LucideIcons.barChart,
+                  userProfile.locale == 'ja'
+                      ? '在庫状況や人気銘柄を分析。ビジネスの意思決定をデータで支援します。'
+                      : 'Analyze inventory and popular brands. Support business decisions with data insights.',
+                );
+                return;
+              }
+            } else {
+              // 個人モード: Scan (index 1) がPro限定
+              if (index == 1) {
+                _showProOnlyDialog(
+                  context,
+                  t['scan'],
+                  LucideIcons.scanLine,
+                  userProfile.locale == 'ja'
+                      ? 'QRコードをスキャンして、酒の情報を素早く登録。AR表示で楽しく記録できます。'
+                      : 'Scan QR codes to quickly register sake information. Enjoy recording with AR display.',
+                );
+                return;
+              }
+            }
+          }
+
+          // 通常のタブ遷移
           setState(() {
             _currentIndex = index;
             ref.read(currentTabIndexProvider.notifier).setIndex(index); // Update global tab state