fix: 大纲修改意见输入框改 textarea，增高并完整显示 placeholder

- input 改为 textarea + auto-height，支持多行输入
- min-height 64rpx 保证 placeholder 完整显示（原来被压扁截断）
- max-height 120rpx 限制约 2 行，超出滚动显示最新底部内容
- line-height 1.5 比例协调，改动幅度小

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

mini-program/src/pages/main/ScriptView.vue

@@ -157,7 +157,7 @@
                   </view>
                 </view>
                 <view v-if="!msg.confirmed" class="outline-actions">
-                  <input v-model="msg.feedback" placeholder="如需修改请输入意见" class="outline-feedback" />
+                  <textarea v-model="msg.feedback" placeholder="如需修改请输入意见" class="outline-feedback" auto-height />
                   <view class="outline-buttons">
                     <view class="btn-secondary" @click="modifyOutline(msg)">修改大纲</view>
                     <view class="btn-primary" @click="confirmOutline(msg)">确认大纲</view>
@@ -2285,11 +2285,14 @@ onUnmounted(() => {
 
 .outline-feedback {
   width: 100%;
-  padding: 20rpx;
+  min-height: 64rpx;
+  max-height: 120rpx;
+  padding: 16rpx 20rpx;
   background: rgba(255, 255, 255, 0.05);
   border-radius: 12rpx;
   color: #ffffff;
   font-size: 28rpx;
+  line-height: 1.5;
   margin-bottom: 24rpx;
   box-sizing: border-box;
 }
@@ -3738,11 +3741,14 @@ onUnmounted(() => {
 
 .outline-feedback {
   width: 100%;
-  padding: 20rpx;
+  min-height: 64rpx;
+  max-height: 120rpx;
+  padding: 16rpx 20rpx;
   background: rgba(255, 255, 255, 0.05);
   border-radius: 12rpx;
   color: #ffffff;
   font-size: 28rpx;
+  line-height: 1.5;
   margin-bottom: 16rpx;
   box-sizing: border-box;
 }