[Refactor] UINavigationController 기반 코디네이터 적용

Projects/App/Sources/View/AppRootView.swift

@@ -50,11 +50,14 @@ private extension AppRootView {
         if let route = currentRoute {
             switch route {
             case .login:
-                LoginRootView { nickname in
-                    handleLoginCompleted(nickname: nickname)
-                } onSignupCompleted: { nickname in
-                    handleSignupCompleted(nickname: nickname)
-                }
+                LoginContentView(
+                    onLoginCompleted: { nickname in
+                        handleLoginCompleted(nickname: nickname)
+                    },
+                    onSignupCompleted: { nickname in
+                        handleSignupCompleted(nickname: nickname)
+                    }
+                )
 
             case .main:
                 LivithMainTabView(nickname: $nickname)

Projects/App/Sources/View/LivithMainTabView.swift

@@ -62,11 +62,11 @@ struct LivithMainTabView: View {
     var body: some View {
         ZStack(alignment: .bottom) {
             TabView(selection: $selectedTab) {
-                HomeRootView(nickname: $nickname)
+                HomeContentView(nickname: $nickname, isTabBarHidden: $isTabBarHidden)
                     .tag(Tab.home)
                     .toolbar(.hidden, for: .tabBar)
 
-                SearchRootView(isTabBarHidden: $isTabBarHidden)
+                SearchContentView(isTabBarHidden: $isTabBarHidden)
                     .tag(Tab.search)
                     .toolbar(.hidden, for: .tabBar)
 

Projects/Core/Project.swift

@@ -32,10 +32,6 @@ let project = Project.make(
             target: .core(.persistence),
             product: .framework
         ),
-        .make(
-            target: .core(.router),
-            product: .framework
-        ),
         .make(
             target: .core(.livithConcurrency),
             product: .framework

Projects/DSKit/Sources/Component/SearchBarView.swift

@@ -14,19 +14,23 @@ public struct SearchBarView: View {
 
     @Binding var input: String
     @FocusState private var isFocused: Bool
-    var onChange: () -> Void
-    var onClear: () -> Void
-    var onSubmit: () -> Void
+
+    private let onBack: () -> Void
+    private let onChange: () -> Void
+    private let onClear: () -> Void
+    private let onSubmit: () -> Void
 
     // MARK: - LifeCycle
 
     public init(
         input: Binding<String>,
+        onBack: @escaping () -> Void,
         onChange: @escaping () -> Void,
         onClear: @escaping () -> Void,
         onSubmit: @escaping () -> Void
     ) {
         self._input = input
+        self.onBack = onBack
         self.onChange = onChange
         self.onClear = onClear
         self.onSubmit = onSubmit
@@ -50,7 +54,7 @@ private extension SearchBarView {
     @ViewBuilder
     func backButton() -> some View {
         Button (action: {
-            // TODO: 화면 전환 구현
+            onBack()
         }) {
             Image.livithIcon(.backLineDefault)
                 .resizable()

Projects/DSKit/Sources/Coordinator/Coordinator.swift

@@ -0,0 +1,110 @@
+//
+//  Coordinator.swift
+//  DSKit
+//
+//  Created by 김진웅 on 12/27/25.
+//  Copyright © 2025 Livith. All rights reserved.
+//
+
+import UIKit
+
+/// 화면 전환 흐름을 관리하는 코디네이터 추상화.
+///
+/// - Note: `@MainActor`에서 동작하며 모든 UI 관련 트랜잭션을
+///   메인 스레드에서 안전하게 처리합니다.
+/// - Important: 코디네이터는 네비게이션 상태 일관성을 유지해야 하며,
+///   `buildViewController(for:)`는 주어진 `Route`에 대한 화면 생성을
+///   명확하고 예측 가능하게 구현해야 합니다.
+///
+/// 제네릭 파라미터
+/// - `R`: 화면 전환을 정의하는 `Route` 타입
+@MainActor
+public protocol Coordinator: AnyObject {
+    associatedtype R: Route
+
+    /// 화면 전환을 주도하는 루트 `UINavigationController`.
+    var navigationController: UINavigationController { get }
+
+    /// 주어진 `route`에 대응하는 화면을 생성합니다.
+    /// - Parameter route: 화면을 생성할 `Route`
+    /// - Returns: 생성된 `UIViewController`
+    ///
+    /// - Tip: SwiftUI의 `View`를 사용해 화면을 구성한다면
+    ///   UIKit과의 호환을 위해 `UIHostingController(rootView:)`로 감싸서 반환하세요.
+    ///
+    ///   예시:
+    ///   ```swift
+    ///   func buildViewController(for route: AppRoute) -> UIViewController {
+    ///       switch route {
+    ///       case .home:
+    ///           let view = HomeView(viewModel: HomeViewModel())
+    ///           return UIHostingController(rootView: view)
+    ///       case .detail(let id):
+    ///           let view = DetailView(id: id)
+    ///           return UIHostingController(rootView: view)
+    ///       }
+    ///   }
+    ///   ```
+    func buildViewController(for route: R) -> UIViewController
+
+    /// 코디네이터 시작 지점. 초기 화면 진입 로직을 구현합니다.
+    func start()
+}
+
+public extension Coordinator {
+    /// 지정한 `route`로 화면을 푸시합니다.
+    /// - Parameters:
+    ///   - route: 이동할 대상 `Route`
+    ///   - animated: 애니메이션 여부. 기본값은 `true`
+    func push(to route: R, animated: Bool = true) {
+        let viewController = buildViewController(for: route)
+        navigationController.pushViewController(viewController, animated: true)
+    }
+
+    /// 현재 화면을 하나 뒤로 되돌립니다.
+    /// - Parameter animated: 애니메이션 여부. 기본값은 `true`
+    func pop(animated: Bool = true) {
+        navigationController.popViewController(animated: animated)
+    }
+
+    /// 루트 화면까지 되돌립니다.
+    /// - Parameter animated: 애니메이션 여부. 기본값은 `true`
+    func popToRoot(animated: Bool = true) {
+        navigationController.popToRootViewController(animated: animated)
+    }
+
+    /// 지정한 `route`를 모달로 표시합니다.
+    /// - Parameters:
+    ///   - route: 표시할 대상 `Route`
+    ///   - animated: 애니메이션 여부. 기본값은 `true`
+    ///   - presentationStyle: `UIModalPresentationStyle` 지정 시 해당 스타일로 표시
+    ///   - transitionStyle: `UIModalTransitionStyle` 지정 시 해당 전환 효과 적용
+    ///   - completion: 표시 완료 후 호출되는 클로저
+    func present(
+        to route: R, 
+        animated: Bool = true, 
+        presentationStyle: UIModalPresentationStyle? = nil,
+        transitionStyle: UIModalTransitionStyle? = nil,
+        completion: (() -> Void)? = nil
+    ) {
+        let viewController = buildViewController(for: route)
+
+        if let style = presentationStyle {
+            viewController.modalPresentationStyle = style
+        }
+
+        if let style = transitionStyle {
+            viewController.modalTransitionStyle = style
+        }
+
+        navigationController.present(viewController, animated: animated, completion: completion)
+    }
+
+    /// 현재 표시 중인 모달을 닫습니다.
+    /// - Parameters:
+    ///   - animated: 애니메이션 여부. 기본값은 `true`
+    ///   - completion: 닫기 완료 후 호출되는 클로저
+    func dismiss(animated: Bool = true, completion: (() -> Void)? = nil) {
+        navigationController.dismiss(animated: animated, completion: completion)
+    }
+}

Projects/Core/Router/Sources/Route.swift → Projects/DSKit/Sources/Coordinator/Route.swift

@@ -1,11 +1,11 @@
 //
 //  Route.swift
-//  core
+//  DSKit
 //
-//  Created by 김진웅 on 10/12/25.
+//  Created by 김진웅 on 12/27/25.
 //  Copyright © 2025 Livith. All rights reserved.
 //
 
 import Foundation
 
-public protocol Route: Hashable, Identifiable {}
+public protocol Route: Hashable {}

Projects/Home/HomeFeature/Sources/Coordinator/EnvironmentValues+HomeCoordinator.swift

@@ -0,0 +1,20 @@
+//
+//  EnvironmentValues+HomeCoordinator.swift
+//  HomeFeature
+//
+//  Created by 김진웅 on 12/27/25.
+//  Copyright © 2025 Livith. All rights reserved.
+//
+
+import SwiftUI
+
+private struct HomeCoordinatorKey: EnvironmentKey {
+    static let defaultValue: HomeCoordinator? = nil
+}
+
+extension EnvironmentValues {
+    var homeCoordinator: HomeCoordinator? {
+        get { self[HomeCoordinatorKey.self] }
+        set { self[HomeCoordinatorKey.self] = newValue }
+    }
+}

Projects/Home/HomeFeature/Sources/Coordinator/HomeContentView.swift

@@ -0,0 +1,68 @@
+//
+//  HomeContentView.swift
+//  HomeFeature
+//
+//  Created by 김진웅 on 12/27/25.
+//  Copyright © 2025 Livith. All rights reserved.
+//
+
+import SwiftUI
+import UIKit
+
+public struct HomeContentView: View {
+    @State private var coordinator: HomeCoordinator
+    @Binding private var isTabBarHidden: Bool
+
+    public init(nickname: Binding<String>, isTabBarHidden: Binding<Bool>) {
+        self._coordinator = State(initialValue: HomeCoordinator(nickname: nickname))
+        self._isTabBarHidden = isTabBarHidden
+    }
+
+    public var body: some View {
+        HomeNavigationHost(coordinator: coordinator, isTabBarHidden: $isTabBarHidden)
+            .ignoresSafeArea()
+    }
+}
+
+// MARK: - NavigationHost
+
+private extension HomeContentView {
+    struct HomeNavigationHost: UIViewControllerRepresentable {
+        let coordinator: HomeCoordinator
+        @Binding var isTabBarHidden: Bool
+
+        func makeCoordinator() -> NavDelegate {
+            NavDelegate(isTabBarHidden: $isTabBarHidden)
+        }
+
+        final class NavDelegate: NSObject, UINavigationControllerDelegate {
+            @Binding var isTabBarHidden: Bool
+
+            init(isTabBarHidden: Binding<Bool>) {
+                self._isTabBarHidden = isTabBarHidden
+            }
+
+            func navigationController(
+                _ navigationController: UINavigationController,
+                willShow viewController: UIViewController,
+                animated: Bool
+            ) {
+                let stackCount = navigationController.viewControllers.count
+                Task { @MainActor in
+                    isTabBarHidden = stackCount > 1
+                }
+            }
+        }
+
+        func makeUIViewController(context: Context) -> UINavigationController {
+            let nav = coordinator.navigationController
+            nav.delegate = context.coordinator
+            if nav.viewControllers.isEmpty {
+                coordinator.start()
+            }
+            return nav
+        }
+
+        func updateUIViewController(_ uiViewController: UINavigationController, context: Context) {}
+    }
+}