feat(ios): tab tabanlı navigasyon ve okuma durumu takibi ekle

ios/Bookibra/App/AppRouter.swift

@@ -3,17 +3,25 @@ import SwiftUI
 
 @MainActor
 final class AppRouter: ObservableObject {
+    enum Tab: Hashable {
+        case library
+        case discover
+        case stats
+        case profile
+    }
+
     enum Route: Hashable {
-        case addBooks
         case category(name: String)
         case detail(BookRemote)
     }
 
     @Published var isAuthenticated = false
+    @Published var selectedTab: Tab = .library
     @Published var path: [Route] = []
 
     func resetToHome() {
         path.removeAll()
+        selectedTab = .library
     }
 }
 

ios/Bookibra/App/BookibraApp.swift

@@ -33,15 +33,13 @@ private struct RootView: View {
         NavigationStack(path: $router.path) {
             Group {
                 if router.isAuthenticated {
-                    HomeView(viewModel: HomeViewModel())
+                    MainTabView()
                 } else {
                     AuthView(viewModel: AuthViewModel(authService: dependencies.authService, keychain: dependencies.keychain))
                 }
             }
             .navigationDestination(for: AppRouter.Route.self) { route in
                 switch route {
-                case .addBooks:
-                    AddBooksView(viewModel: AddBooksViewModel(booksService: dependencies.booksService))
                 case .category(let name):
                     CategoryListView(viewModel: CategoryViewModel(categoryName: name))
                 case .detail(let book):
@@ -70,3 +68,66 @@ private struct RootView: View {
         }
     }
 }
+
+private struct MainTabView: View {
+    @EnvironmentObject private var router: AppRouter
+    @Environment(\.dependencies) private var dependencies
+
+    var body: some View {
+        TabView(selection: $router.selectedTab) {
+            HomeView(viewModel: HomeViewModel())
+                .tabItem {
+                    Label("Library", systemImage: "books.vertical")
+                }
+                .tag(AppRouter.Tab.library)
+
+            AddBooksView(viewModel: AddBooksViewModel(booksService: dependencies.booksService))
+                .tabItem {
+                    Label("Discover", systemImage: "sparkle.magnifyingglass")
+                }
+                .tag(AppRouter.Tab.discover)
+
+            StatsPlaceholderView()
+                .tabItem {
+                    Label("Stats", systemImage: "chart.line.uptrend.xyaxis")
+                }
+                .tag(AppRouter.Tab.stats)
+
+            ProfilePlaceholderView()
+                .tabItem {
+                    Label("Profile", systemImage: "person.crop.circle")
+                }
+                .tag(AppRouter.Tab.profile)
+        }
+    }
+}
+
+private struct StatsPlaceholderView: View {
+    var body: some View {
+        ContentUnavailableView {
+            Label("Stats", systemImage: "chart.bar.xaxis")
+        } description: {
+            Text("Reading analytics yakında eklenecek.")
+        }
+    }
+}
+
+private struct ProfilePlaceholderView: View {
+    @EnvironmentObject private var router: AppRouter
+    @Environment(\.dependencies) private var dependencies
+
+    var body: some View {
+        NavigationStack {
+            List {
+                Section("Session") {
+                    Button("Logout", role: .destructive) {
+                        _ = dependencies.keychain.delete(for: AuthViewModel.tokenKey)
+                        router.isAuthenticated = false
+                        router.resetToHome()
+                    }
+                }
+            }
+            .navigationTitle("Profile")
+        }
+    }
+}