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/course_content_test.dart

@@ -1,7 +1,9 @@
+import 'dart:convert';
 import 'dart:io';
 
 import 'package:flutter_test/flutter_test.dart';
 import 'package:kouyu_english/core/courses/courses.dart';
+import 'package:kouyu_english/core/courses/course_pack.dart';
 
 import '../tool/courses/course_validator.dart';
 
@@ -56,4 +58,16 @@ void main() {
     ).validate();
     expect(report.errors.map((issue) => '$issue'), isEmpty);
   });
+
+  test('the course parser keeps item links and extra model sentences', () {
+    final unit =
+        jsonDecode(File('assets/courses/A1/A1-U01.json').readAsStringSync())
+            as Map<String, dynamic>;
+    final segment = PackSegment.fromJson(
+      (unit['segments'] as List).first as Map<String, dynamic>,
+    );
+    expect(segment.speakingItemIds, ['A1-U01-P01', 'A1-U01-P04']);
+    expect(segment.speakingExamples, isNotEmpty);
+    expect(segment.speakingChunks.join(' '), segment.speakingText);
+  });
 }