fix: 修复左侧面板内容溢出不可见问题

- aside 添加 h-screen 确保高度约束
- 内容区添加 min-h-0 确保 flex 子元素正确滚动

src/components/WriterPanel.vue

@@ -1,5 +1,5 @@
 <template>
-  <aside class="w-[400px] flex flex-col border-r border-slate-700 bg-slate-800 shrink-0">
+  <aside class="w-[400px] h-screen flex flex-col border-r border-slate-700 bg-slate-800 shrink-0">
     <!-- 头部 -->
     <header class="p-4 border-b border-slate-700 flex items-center justify-between">
       <div class="flex items-center gap-4">
@@ -17,7 +17,7 @@
     </header>
 
     <!-- 内容区 -->
-    <div class="flex-1 overflow-y-auto p-4 space-y-6">
+    <div class="flex-1 overflow-y-auto p-4 space-y-6 min-h-0">
       <!-- 写作任务 -->
       <section>
         <div class="flex justify-between items-center mb-2">