修复测验页空白问题，测验入口改为文字按钮

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

LearnEnglish/LearnEnglish/Views/QuizView.swift

@@ -6,13 +6,18 @@ struct QuizView: View {
     @Environment(SpeechService.self) private var speech
     @Environment(\.dismiss) private var dismiss
 
-    @State private var questions: [QuizQuestion] = []
+    @State private var questions: [QuizQuestion]
     @State private var currentIndex = 0
     @State private var selectedOption: String?
     @State private var wrongWords: [Word] = []
     @State private var finished = false
     @State private var startDate = Date.now
 
+    init(config: QuizConfig) {
+        self.config = config
+        _questions = State(initialValue: QuizGenerator.makeQuestions(mode: config.mode, words: config.words))
+    }
+
     private var current: QuizQuestion? {
         questions.indices.contains(currentIndex) ? questions[currentIndex] : nil
     }
@@ -33,9 +38,6 @@ struct QuizView: View {
         }
         .navigationTitle(config.mode.rawValue)
         .navigationBarTitleDisplayMode(.inline)
-        .onAppear {
-            if questions.isEmpty { restart() }
-        }
     }
 
     private func questionView(_ question: QuizQuestion) -> some View {

LearnEnglish/LearnEnglish/Views/WordListView.swift

@@ -24,7 +24,7 @@ struct WordListView: View {
                     Button("英选汉") { startQuiz(.enToZh) }
                     Button("汉选英") { startQuiz(.zhToEn) }
                 } label: {
-                    Label("测验", systemImage: "questionmark.circle")
+                    Text("测验")
                 }
             }
         }