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/lib/core/courses/assessment.dart

@@ -22,7 +22,9 @@ class AssessmentTask {
     skill: AssessmentSkill.values.byName(json['skill'] as String),
     prompt: json['prompt'] as String? ?? '',
     audio: json['audio'] as String?,
-    choices: [for (final choice in json['choices'] as List? ?? const []) '$choice'],
+    choices: [
+      for (final choice in json['choices'] as List? ?? const []) '$choice',
+    ],
     answerIndex: json['answerIndex'] as int?,
     accept: [
       for (final group in json['accept'] as List? ?? const [])
@@ -102,10 +104,7 @@ AssessmentPack? replacementFor(String packId) =>
 /// The pack whose results [packId] counts toward: the original of a
 /// replacement pack, otherwise [packId] itself.
 String canonicalAssessmentPackId(String packId) =>
-    assessmentPacks
-        .where((pack) => pack.id == packId)
-        .firstOrNull
-        ?.replaces ??
+    assessmentPacks.where((pack) => pack.id == packId).firstOrNull?.replaces ??
     packId;
 
 /// Local check of an open task with the same rule engine as the lessons: it