docs: 学习目标定为日常与旅行，重写学习路线与词汇分层规格

- 取消学习目标选择，不做学校场景，工作场景延后
- 词汇分两层：核心表达与分级词池，写明词池来源与校验方式
- 补充复习节点、掌握判定与阶段评估的规则说明

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

Doc/learning-app-prototype.html

@@ -123,7 +123,7 @@
       <div class="brand">开口英语</div>
       <p class="small">M1 · 手机优先原型</p>
       <div class="screen-list" role="group" aria-label="选择页面">
-        <button class="screen-link" data-screen-target="welcome" aria-pressed="false" type="button">01 目标设置</button>
+        <button class="screen-link" data-screen-target="welcome" aria-pressed="false" type="button">01 欢迎与每日时长</button>
         <button class="screen-link" data-screen-target="placement" aria-pressed="false" type="button">02 起点定位</button>
         <button class="screen-link" data-screen-target="home" aria-pressed="true" type="button">03 首页</button>
         <button class="screen-link" data-screen-target="map" aria-pressed="false" type="button">04 学习地图</button>
@@ -150,8 +150,7 @@
             <div class="eyebrow">欢迎</div>
             <h1>每天 20 分钟，<br>说出能用的英语。</h1>
             <p class="bodycopy">从真实生活场景开始，先做到听得懂、说得清。</p>
-            <div class="slot selected"><div class="slot-title">你的主要目标</div><div class="assist"><span class="chip">日常生活</span><span class="chip">旅行</span><span class="chip">工作起步</span></div></div>
-            <div class="slot"><div class="slot-title">每天学习多久？</div><div class="assist"><span class="chip">10 分钟</span><span class="chip" style="background:var(--ka-soft-green);color:var(--ka-green)">20 分钟</span><span class="chip">30 分钟</span></div></div>
+                        <div class="slot selected"><div class="slot-title">每天学习多久？</div><div class="assist"><span class="chip">10 分钟</span><span class="chip" style="background:var(--ka-soft-green);color:var(--ka-green)">20 分钟</span><span class="chip">30 分钟</span></div></div>
             <button class="primary" data-go="placement" type="button">继续</button>
           </div>
         </section>
@@ -270,7 +269,7 @@
       </div>
     </main>
     <aside class="panel flow-panel" aria-label="原型流程说明">
-      <p class="legend-title">M1 流程</p><div class="flow"><div class="flow-row"><strong>首次使用</strong>目标设置 → 起点定位 → 首页</div><div class="flow-row active"><strong>日常学习</strong>首页 → 词汇预热 → 课程 → AI 对话 → 总结</div><div class="flow-row"><strong>查词帮助</strong>点词/短语 → 查词卡 → 回到原步骤</div><div class="flow-row"><strong>纠错保护</strong>低置信转写 → 确认 / 修改 / 重说</div><div class="flow-row"><strong>巩固</strong>总结 → 次日微对话复习</div><div class="flow-row"><strong>设备</strong>手机优先；Mac 使用更宽的同一学习结构</div></div><p class="legend-title" style="margin-top:20px">设计原则</p><span class="chip">一个主任务</span><span class="chip">预热不算掌握</span><span class="chip">短语优先查词</span><span class="chip">口音可理解即接受</span><span class="chip">一次只纠正一个点</span><span class="chip">语音失败可改文字</span>
+      <p class="legend-title">M1 流程</p><div class="flow"><div class="flow-row"><strong>首次使用</strong>每日时长 → 起点定位 → 首页</div><div class="flow-row active"><strong>日常学习</strong>首页 → 词汇预热 → 课程 → AI 对话 → 总结</div><div class="flow-row"><strong>查词帮助</strong>点词/短语 → 查词卡 → 回到原步骤</div><div class="flow-row"><strong>纠错保护</strong>低置信转写 → 确认 / 修改 / 重说</div><div class="flow-row"><strong>巩固</strong>总结 → 次日微对话复习</div><div class="flow-row"><strong>设备</strong>手机优先；Mac 使用更宽的同一学习结构</div></div><p class="legend-title" style="margin-top:20px">设计原则</p><span class="chip">一个主任务</span><span class="chip">预热不算掌握</span><span class="chip">短语优先查词</span><span class="chip">口音可理解即接受</span><span class="chip">一次只纠正一个点</span><span class="chip">语音失败可改文字</span>
     </aside>
   </div>
   <script>