feat: Add ChatDetailScreen and implement chat navigation with animated transitions

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

@@ -26,6 +26,8 @@ import com.rosetta.messenger.data.PreferencesManager
 import com.rosetta.messenger.ui.auth.AccountInfo
 import com.rosetta.messenger.ui.auth.AuthFlow
 import com.rosetta.messenger.ui.chats.ChatsListScreen
+import com.rosetta.messenger.ui.chats.ChatDetailScreen
+import com.rosetta.messenger.network.SearchUser
 import com.rosetta.messenger.ui.onboarding.OnboardingScreen
 import com.rosetta.messenger.ui.splash.SplashScreen
 import com.rosetta.messenger.ui.theme.RosettaAndroidTheme
@@ -214,44 +216,84 @@ fun MainScreen(
     val accountPublicKey = account?.publicKey ?: "04c266b98ae5"
     val privateKeyHash = account?.privateKeyHash ?: ""
     
-    ChatsListScreen(
-        isDarkTheme = isDarkTheme,
-        accountName = accountName,
-        accountPhone = accountPhone,
-        accountPublicKey = accountPublicKey,
-        privateKeyHash = privateKeyHash,
-        onToggleTheme = onToggleTheme,
-        onProfileClick = {
-            // TODO: Navigate to profile
+    // Навигация между экранами
+    var selectedUser by remember { mutableStateOf<SearchUser?>(null) }
+    
+    // Анимированный переход между чатами
+    AnimatedContent(
+        targetState = selectedUser,
+        transitionSpec = {
+            if (targetState != null) {
+                // Открытие чата - слайд слева
+                slideInHorizontally(
+                    initialOffsetX = { it },
+                    animationSpec = tween(300)
+                ) togetherWith slideOutHorizontally(
+                    targetOffsetX = { -it / 3 },
+                    animationSpec = tween(300)
+                )
+            } else {
+                // Закрытие чата - слайд справа
+                slideInHorizontally(
+                    initialOffsetX = { -it / 3 },
+                    animationSpec = tween(300)
+                ) togetherWith slideOutHorizontally(
+                    targetOffsetX = { it },
+                    animationSpec = tween(300)
+                )
+            }
         },
-        onNewGroupClick = {
-            // TODO: Navigate to new group
-        },
-        onContactsClick = {
-            // TODO: Navigate to contacts
-        },
-        onCallsClick = {
-            // TODO: Navigate to calls
-        },
-        onSavedMessagesClick = {
-            // TODO: Navigate to saved messages
-        },
-        onSettingsClick = {
-            // TODO: Navigate to settings
-        },
-        onInviteFriendsClick = {
-            // TODO: Share invite link
-        },
-        onSearchClick = {
-            // TODO: Show search
-        },
-        onNewChat = {
-            // TODO: Show new chat screen
-        },
-        onUserSelect = { user ->
-            // TODO: Navigate to chat with selected user
-            android.util.Log.d("MainScreen", "User selected: ${user.publicKey}")
-        },
-        onLogout = onLogout
-    )
+        label = "chatNavigation"
+    ) { user ->
+        if (user != null) {
+            // Экран чата
+            ChatDetailScreen(
+                user = user,
+                currentUserPublicKey = accountPublicKey,
+                isDarkTheme = isDarkTheme,
+                onBack = { selectedUser = null }
+            )
+        } else {
+            // Список чатов
+            ChatsListScreen(
+                isDarkTheme = isDarkTheme,
+                accountName = accountName,
+                accountPhone = accountPhone,
+                accountPublicKey = accountPublicKey,
+                privateKeyHash = privateKeyHash,
+                onToggleTheme = onToggleTheme,
+                onProfileClick = {
+                    // TODO: Navigate to profile
+                },
+                onNewGroupClick = {
+                    // TODO: Navigate to new group
+                },
+                onContactsClick = {
+                    // TODO: Navigate to contacts
+                },
+                onCallsClick = {
+                    // TODO: Navigate to calls
+                },
+                onSavedMessagesClick = {
+                    // TODO: Navigate to saved messages
+                },
+                onSettingsClick = {
+                    // TODO: Navigate to settings
+                },
+                onInviteFriendsClick = {
+                    // TODO: Share invite link
+                },
+                onSearchClick = {
+                    // TODO: Show search
+                },
+                onNewChat = {
+                    // TODO: Show new chat screen
+                },
+                onUserSelect = { user ->
+                    selectedUser = user
+                },
+                onLogout = onLogout
+            )
+        }
+    }
 }