feat: 도서 등록 Flow 추가

src/Projects/BKDesign/Sources/Components/Button/BKButtonGroup.swift

@@ -99,7 +99,7 @@ public class BKButtonGroup: UIView {
         switch layout {
         case .horizontal:
             stackView.axis = .horizontal
-            stackView.distribution = .fillProportionally
+            stackView.distribution = .fillEqually
             stackView.alignment = .fill
             buttons.forEach { $0.isFullWidth = false }
 

src/Projects/BKPresentation/Sources/MainFlow/Search/View/BookRegistrationStatusView.swift

@@ -0,0 +1,82 @@
+// Copyright © 2025 Booket. All rights reserved
+
+import BKDesign
+import SnapKit
+import UIKit
+
+enum BookRegistrationStatus: String {
+    case before = "읽기 전"
+    case inProgress = "읽는 중"
+    case after = "독서 완료"
+}
+
+final class BookRegistrationStatusView: UIView {
+    private let stackView = UIStackView()
+    private let statuses: [BookRegistrationStatus] = [.before, .inProgress, .after]
+    private var buttons: [BKButton] = []
+
+    var onSelected: (() -> Void)?
+
+    private(set) var selectedStatus: BookRegistrationStatus? {
+        didSet {
+            onSelected?()
+        }
+    }
+
+    override init(frame: CGRect) {
+        super.init(frame: frame)
+        setupView()
+    }
+
+    required init?(coder: NSCoder) {
+        super.init(coder: coder)
+        setupView()
+    }
+}
+
+private extension BookRegistrationStatusView {
+    func setupView() {
+        addSubview(stackView)
+        stackView.axis = .horizontal
+        stackView.spacing = BKInset.inset2
+        stackView.distribution = .fillEqually
+        stackView.alignment = .fill
+
+        stackView.snp.makeConstraints {
+            $0.top.equalToSuperview()
+                .inset(BKInset.inset5)
+            $0.bottom.equalToSuperview()
+                .inset(BKInset.inset3)
+            $0.leading.trailing.equalToSuperview()
+        }
+
+        statuses.forEach { status in
+            let button = BKButton.secondary(title: status.rawValue)
+            button.addAction(UIAction { [weak self] _ in
+                self?.select(status: status)
+            }, for: .touchUpInside)
+
+            button.snp.makeConstraints {
+                $0.height.equalTo(LayoutConstants.buttonHeight)
+            }
+            buttons.append(button)
+            stackView.addArrangedSubview(button)
+        }
+    }
+
+    func select(status: BookRegistrationStatus) {
+        selectedStatus = status
+
+        for (index, button) in buttons.enumerated() {
+            if statuses[index] == status {
+                button.style = .tertiary
+            } else {
+                button.style = .secondary
+            }
+        }
+    }
+
+    enum LayoutConstants {
+        static let buttonHeight: CGFloat = 52
+    }
+}

src/Projects/BKPresentation/Sources/MainFlow/Search/View/SearchView.swift

@@ -234,6 +234,16 @@ extension SearchView: UICollectionViewDelegate {
             eventPublisher.send(.loadNextPage)
         }
     }
+
+    func collectionView(
+        _ collectionView: UICollectionView,
+        didSelectItemAt indexPath: IndexPath
+    ) {
+        guard let item = dataSource.itemIdentifier(for: indexPath) else { return }
+        if case let .result(book) = item {
+            eventPublisher.send(.upsertBook(book.isbn))
+        }
+    }
 }
 
 private extension SearchView {

src/Projects/BKPresentation/Sources/MainFlow/Search/View/SearchViewController.swift

@@ -1,12 +1,15 @@
 // Copyright © 2025 Booket. All rights reserved
 
+import BKCore
+import BKDesign
 import Combine
 import UIKit
 
 enum SearchViewEvent: Equatable {
     case search(String)
     case loadNextPage
     case deleteRecentQuery(String)
+    case upsertBook(String)
 }
 
 final class SearchViewController: BaseViewController<SearchView> {
@@ -64,6 +67,17 @@ final class SearchViewController: BaseViewController<SearchView> {
                 self?.viewModel.send(.deleteRecentQuery(query))
             }
             .store(in: &cancellable)
+
+        contentView.eventPublisher
+            .compactMap { event -> String? in
+                if case let .upsertBook(isbn) = event { return isbn }
+                return nil
+            }
+            .removeDuplicates()
+            .sink { [weak self] query in
+                self?.presentBookRegistration(with: query)
+            }
+            .store(in: &cancellable)
     }
 
     override func bindState() {
@@ -85,3 +99,58 @@ final class SearchViewController: BaseViewController<SearchView> {
             .store(in: &cancellable)
     }
 }
+
+private extension SearchViewController {
+    func presentBookRegistration(with isbn: String) {
+        let statusView = BookRegistrationStatusView()
+        let sheet = BKBottomSheetViewController(
+            title: "등록 옵션",
+            style: .leadingCloseButton,
+            suppliedContentStyle: .lower(statusView),
+            buttonConfiguration: .singleFullButton(
+                title: "도서 등록"
+            ) { [weak self] in
+                guard let selected = statusView.selectedStatus else { return }
+                self?.dismiss(animated: true)
+                self?.handleRegistrationSelection(status: selected, isbn: isbn)
+            }
+        )
+        sheet.button?.primaryButton?.isEnabled = false
+        statusView.onSelected = {
+            sheet.button?.primaryButton?.isEnabled = true
+        }
+        sheet.show(from: self, animated: true)
+    }
+
+    func handleRegistrationSelection(status: BookRegistrationStatus, isbn: String) {
+        Log.debug("선택된 책: \(isbn), 상태: \(status.rawValue)", logger: AppLogger.ui)
+//        viewModel.send(.upsertBook(isbn))
+        // TODO: - upsert 성공 시 따라오는 동작으로 변경해야 함
+        presentNoteSuggestion(with: isbn)
+    }
+
+    func presentNoteSuggestion(with isbn: String) {
+        // TODO: - 그래픽 디자인 작업 이후 변경
+        let graphic = BKImage.Icon.bookmark
+        let graphicView = UIImageView(image: graphic)
+        let sheet = BKBottomSheetViewController(
+            title: "도서가 등록되었어요!",
+            subtitle: "독서 기록을 시작할까요?",
+            style: .centered,
+            suppliedContentStyle: .upper(graphicView),
+            buttonConfiguration: .twoButtonGroup(
+                leftTitle: "아니요, 나중에요",
+                rightTitle: "네, 시작할게요!",
+                leftAction: { [weak self] in
+                    self?.dismiss(animated: true)
+                },
+                rightAction: { [weak self] in
+                    Log.debug("선택된 책 \(isbn), 등록 시작", logger: AppLogger.ui)
+                    self?.dismiss(animated: true)
+                }
+            )
+        )
+
+        sheet.show(from: self, animated: true)
+    }
+}

src/Projects/BKPresentation/Sources/MainFlow/Search/ViewModel/SearchViewModel.swift

@@ -28,6 +28,7 @@ final class SearchViewModel: BaseViewModel {
         case search(String)
         case loadNextPage
         case deleteRecentQuery(String)
+//        case upsertBook(String)
         case fetchRecentQueriesSuccessed([String])
         case fetchSearchResultSuccessed((books: [Book], totalResults: Int))
         case fetchNextPageSuccessed([Book])
@@ -38,6 +39,7 @@ final class SearchViewModel: BaseViewModel {
         case deleteRecentQuery(String)
         case searchResult(String)
         case loadNextPage
+//        case upsert(Book)
     }
 
     @Published private var state = State()