feat: 独立词库、三向认词与当日快闪复习

## 独立词库理解词原先只能跟着课程单元走，学完 A0 十课词汇量只增加约 22 个实词，不足以解决"记不住单词"。新增一份独立词库 assets/words/wordbank.json （2748 词，A1–B1），挂进 receptiveWordRegistry 的合成单元 bank-A1/A2/B1，完全复用理解词已有的状态机，不依赖课程进度，第一天就能用。数据来源、许可与合成规则记在 tool/words/DATA-NOTE.md：CEFR-J 定等级、公开词书提供音标、AI 重写全部释义并生成例句、OpenSubtitles 提供口语词频。词书部分为 CC BY-NC-SA 4.0 且上游权利不明，仅供个人非商用；若要分发或上架，须替换音标那一列。 ## 背单词机制 - 间隔阶梯 1/3/7/15/30/60/120 天，连续答对上一级，答错回第一级。原先首次答对后要等 7 天才复习，正是"第二天就忘"的成因。 - 每日新词上限（10 分钟 8 个 / 20 分钟 15 个 / 30 分钟 20 个）。阶梯第一级是次日，今天引入的新词就是明天的工作量。 - 新词按口语频率发放，不再按字母序 —— A1 从 a.m./ability 变成 no/not/know/just。 - 三个方向按层级轮转：看词（英→中）→ 听词（音→中）→ 想词（中→英）。想词题仍是选择题，不要求产出，理解词定位不变，不进升级分母。 - 单词页独立成 tab，首页今日任务卡下方给一张认词入口卡。 ## 用法对照课程 JSON 增加 usage 字段（when/reply/swap/confuse）：一个句型用在什么场合、对方通常怎么答、还能怎么说、跟哪个学过的句型容易混。知道 How are you? 的意思，不等于知道它不是用来问名字的。 ## 复习流 - 当日快闪（recap）独立成队列，不占复习预算，也不计入积压。 - 只发放当日预算内的量，其余保持到期状态等下次，不悄悄丢弃或改期。 - 答错的项隔几题后回来，而不是立刻重问。测试 296 通过，flutter analyze 干净。 Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
2026-09-20 23:54:17 +09:00
parent 1a10ca88e0
commit 6b42b7abc3
52 changed files with 4044 additions and 82 deletions
@@ -59,6 +59,99 @@ void main() {
    expect(failures, isEmpty);
  });

+  test('every A0 pattern says when it is used', () {
+    final missing = [
+      for (final pack in CourseRepository.instance.units)
+        if (pack.level == 'A0')
+          for (final item in pack.coreItems)
+            if (item.type != 'word' && (coreUsage(item.id)?.when ?? '').isEmpty)
+              '${item.id} "${item.en}"',
+    ];
+    expect(
+      missing,
+      isEmpty,
+      reason: '句型要写清什么时候用，否则学会了也不知道该用哪一句',
+    );
+  });
+
+  test('every confusable points at a real taught item with a note', () {
+    final broken = <String>[];
+    for (final pack in CourseRepository.instance.units) {
+      for (final item in pack.coreItems) {
+        for (final other in item.usage.confuse) {
+          if (!isCoreItem(other.id)) broken.add('${item.id} → ${other.id} 不存在');
+          if (other.note.isEmpty) broken.add('${item.id} → ${other.id} 没写区别');
+          if (other.id == item.id) broken.add('${item.id} 指向自己');
+        }
+      }
+    }
+    expect(broken, isEmpty);
+  });
+
+  test('every A0 pattern has something to be told apart from', () {
+    final alone = [
+      for (final pack in CourseRepository.instance.units)
+        if (pack.level == 'A0')
+          for (final item in pack.coreItems)
+            if (item.type != 'word' && item.usage.confuse.isEmpty)
+              '${item.id} "${item.en}"',
+    ];
+    expect(alone, isEmpty, reason: '每个句型都要有一句容易混的，才出得了辨析题');
+  });
+
+  test('a pattern can be told apart from something already taught', () {
+    final order = {
+      for (var i = 0; i < CourseRepository.instance.units.length; i++)
+        CourseRepository.instance.units[i].id: i,
+    };
+    final late = <String>[];
+    for (final pack in CourseRepository.instance.units) {
+      if (pack.level != 'A0') continue;
+      for (final item in pack.coreItems) {
+        if (item.type == 'word' || item.usage.confuse.isEmpty) continue;
+        // The first review of an item comes a day after its own unit, so a
+        // pairing that only names later units has nothing to ask about then.
+        final reachable = item.usage.confuse.any((other) {
+          final unit = coreItemRegistry[other.id]?.unit;
+          return unit != null && (order[unit] ?? 999) <= order[pack.id]!;
+        });
+        if (!reachable) late.add('${item.id} 的易混句都在后面的单元');
+      }
+    }
+    expect(late, isEmpty);
+  });
+
+  test('a contrast question offers the item and something else to pick', () {
+    final broken = <String>[];
+    for (final id in allCoreItemIds) {
+      if ((coreUsage(id)?.confuse ?? const []).isEmpty) continue;
+      final question = coreContrastQuestion(id);
+      if (question == null) {
+        broken.add('$id has confusables but no question');
+        continue;
+      }
+      // Two options is a real choice; more than three turns recall into a
+      // reading exercise.
+      if (question.options.length < 2 || question.options.length > 3) {
+        broken.add('$id has ${question.options.length} options');
+      }
+      // A situation that quotes one of the sentences gives the choice away.
+      for (final option in question.options) {
+        if (question.situation.contains(option)) {
+          broken.add('$id 的情境里写出了选项「$option」');
+        }
+      }
+      if (!question.options.contains(question.answer)) {
+        broken.add('$id answer is not among the options');
+      }
+      // Two sentences a learner has to tell apart cannot be the same string.
+      if (question.options.toSet().length != question.options.length) {
+        broken.add('$id repeats an option');
+      }
+    }
+    expect(broken, isEmpty);
+  });
+
  test('assessment tasks are answerable and replacements point home', () {
    final ids = {for (final pack in assessmentPacks) pack.id};
    final failures = <String>[];