feat: 完善听力口语辅助状态记录、练习分块与复习抽查间隔机制

kouyu_english/test/answer_confirmation_test.dart

@@ -128,12 +128,12 @@ void main() {
     );
     await tester.enterText(find.byType(TextField), 'I am from Hong Kong.');
     await tester.pump();
-    final submit = find.text('我能独立回答');
+    final submit = find.text('检查并提交');
     await tester.ensureVisible(submit);
     await tester.tap(submit);
     await tester.pump();
 
-    expect(find.text('答对了！'), findsOneWidget);
+    expect(find.text('完成练习（未计独立掌握）'), findsOneWidget);
     expect(find.text('你的回答：I am from Hong Kong.'), findsOneWidget);
     expect(find.textContaining("参考说法：I'm from …"), findsOneWidget);
     await tester.tap(find.text('完成今天的复习'));
@@ -208,7 +208,7 @@ void main() {
       await tester.ensureVisible(check);
       await tester.tap(check);
       await tester.pump();
-      expect(find.text('答对了！'), findsOneWidget);
+      expect(find.text('完成练习（不计独立掌握）'), findsOneWidget);
       expect(find.text('AI 补练 · 1/4'), findsOneWidget);
 
       final next = find.text('下一项');