详情页移除入场动画、标题显示分类名，汉选英播放按钮选答后才显示

LearnEnglish/LearnEnglish/Views/QuizViewController.swift

@@ -28,6 +28,12 @@ final class QuizViewController: UIViewController {
     private let promptStack = UIStackView()
     private let inputStack = UIStackView()
     private let resultStack = UIStackView()
+    private let navSpeakerItem = UIBarButtonItem(
+        image: UIImage(systemName: "speaker.wave.2.fill"),
+        style: .plain,
+        target: nil,
+        action: nil
+    )
 
     private var current: QuizQuestion? {
         questions.indices.contains(currentIndex) ? questions[currentIndex] : nil
@@ -110,12 +116,9 @@ final class QuizViewController: UIViewController {
         nextButton.configuration = nextConfig
         nextButton.addAction(UIAction { [weak self] _ in self?.primaryButtonTapped() }, for: .touchUpInside)
 
-        navigationItem.rightBarButtonItem = UIBarButtonItem(
-            image: UIImage(systemName: "speaker.wave.2.fill"),
-            style: .plain,
-            target: self,
-            action: #selector(speakCurrentWord)
-        )
+        navSpeakerItem.target = self
+        navSpeakerItem.action = #selector(speakCurrentWord)
+        navigationItem.rightBarButtonItem = navSpeakerItem
 
         let headerStack = UIStackView(arrangedSubviews: [progressView, countLabel])
         headerStack.axis = .vertical
@@ -163,6 +166,8 @@ final class QuizViewController: UIViewController {
         resultLabel.isHidden = true
         resultPhoneticLabel.isHidden = true
 
+        navigationItem.rightBarButtonItem = config.mode == .zhToEn ? nil : navSpeakerItem
+
         let isSpelling = config.mode == .spelling
         let isDictation = config.mode == .dictation
         let isChoice = !isSpelling && !isDictation
@@ -290,6 +295,7 @@ final class QuizViewController: UIViewController {
                 icon.transform = .identity
             }
         }
+        navigationItem.rightBarButtonItem = navSpeakerItem
         showResult(correct, for: question)
     }