refactor: Clean up OnboardingScreen code for improved readability and maintainability

app/src/main/java/com/rosetta/messenger/MainActivity.kt

@@ -39,6 +39,7 @@ import com.rosetta.messenger.ui.chats.ChatsListScreen
 import com.rosetta.messenger.ui.chats.SearchScreen
 import com.rosetta.messenger.ui.components.OptimizedEmojiCache
 import com.rosetta.messenger.ui.onboarding.OnboardingScreen
+import com.rosetta.messenger.ui.settings.SettingsScreen
 import com.rosetta.messenger.ui.splash.SplashScreen
 import com.rosetta.messenger.ui.theme.RosettaAndroidTheme
 import java.text.SimpleDateFormat
@@ -437,15 +438,18 @@ fun MainScreen(
     // Навигация между экранами
     var selectedUser by remember { mutableStateOf<SearchUser?>(null) }
     var showSearchScreen by remember { mutableStateOf(false) }
+    var showSettingsScreen by remember { mutableStateOf(false) }
 
     // 🔥 TELEGRAM-STYLE анимация - чистый slide БЕЗ прозрачности
     AnimatedContent(
-            targetState = Triple(selectedUser, showSearchScreen, Unit),
+            targetState = Triple(selectedUser, showSearchScreen, showSettingsScreen),
             transitionSpec = {
                 val isEnteringChat = targetState.first != null && initialState.first == null
                 val isExitingChat = targetState.first == null && initialState.first != null
                 val isEnteringSearch = targetState.second && !initialState.second
                 val isExitingSearch = !targetState.second && initialState.second
+                val isEnteringSettings = targetState.third && !initialState.third
+                val isExitingSettings = !targetState.third && initialState.third
 
                 when {
                     // 🚀 Вход в чат - плавный fade
@@ -478,6 +482,18 @@ fun MainScreen(
                                 fadeOut(animationSpec = tween(150))
                     }
 
+                    // ⚙️ Вход в Settings - плавный fade
+                    isEnteringSettings -> {
+                        fadeIn(animationSpec = tween(200)) togetherWith
+                                fadeOut(animationSpec = tween(150))
+                    }
+
+                    // 🔙 Выход из Settings - плавный fade
+                    isExitingSettings -> {
+                        fadeIn(animationSpec = tween(200)) togetherWith
+                                fadeOut(animationSpec = tween(150))
+                    }
+
                     // Default - мгновенный переход
                     else -> {
                         EnterTransition.None togetherWith ExitTransition.None
@@ -485,7 +501,7 @@ fun MainScreen(
                 }
             },
             label = "screenNavigation"
-    ) { (currentUser, isSearchOpen, _) ->
+    ) { (currentUser, isSearchOpen, isSettingsOpen) ->
         when {
             currentUser != null -> {
                 // Экран чата
@@ -525,6 +541,41 @@ fun MainScreen(
                         }
                 )
             }
+            isSettingsOpen -> {
+                // Экран настроек
+                SettingsScreen(
+                        isDarkTheme = isDarkTheme,
+                        accountName = accountName,
+                        accountPhone = accountPhone,
+                        accountPublicKey = accountPublicKey,
+                        onBack = { showSettingsScreen = false },
+                        onToggleTheme = onToggleTheme,
+                        onProfileClick = {
+                            // TODO: Navigate to profile editor
+                        },
+                        onPrivacySecurityClick = {
+                            // TODO: Navigate to privacy settings
+                        },
+                        onNotificationsClick = {
+                            // TODO: Navigate to notifications settings
+                        },
+                        onDataStorageClick = {
+                            // TODO: Navigate to data storage settings
+                        },
+                        onChatSettingsClick = {
+                            // TODO: Navigate to chat settings
+                        },
+                        onLanguageClick = {
+                            // TODO: Navigate to language selection
+                        },
+                        onHelpClick = {
+                            // TODO: Navigate to help center
+                        },
+                        onAboutClick = {
+                            // TODO: Show about dialog
+                        }
+                )
+            }
             else -> {
                 // Список чатов
                 ChatsListScreen(
@@ -558,9 +609,7 @@ fun MainScreen(
                                             online = 1
                                     )
                         },
-                        onSettingsClick = {
-                            // TODO: Navigate to settings
-                        },
+                        onSettingsClick = { showSettingsScreen = true },
                         onInviteFriendsClick = {
                             // TODO: Share invite link
                         },