fix: 修复右侧范式分析结果区域底部内容被截断问题

- main添加h-screen min-h-0确保正确高度
- header添加shrink-0防止压缩
- 内容区添加min-h-0和pb-8确保滚动正常

src/components/MainContent.vue

@@ -1,5 +1,5 @@
 <template>
-  <main class="flex-1 flex flex-col bg-slate-950 relative">
+  <main class="flex-1 flex flex-col bg-slate-950 relative h-screen min-h-0">
     <!-- Prompt调试面板 -->
     <div v-if="showPromptDebug && currentPage === 'writer'" class="absolute inset-0 bg-slate-950/95 z-20 p-8 overflow-auto backdrop-blur-sm">
       <div class="max-w-3xl mx-auto">
@@ -15,7 +15,7 @@
     </div>
 
     <!-- 顶部工具栏 -->
-    <header class="h-14 border-b border-slate-800 flex items-center justify-between px-6 bg-slate-950">
+    <header class="h-14 border-b border-slate-800 flex items-center justify-between px-6 bg-slate-950 shrink-0">
       <span class="text-sm font-medium text-slate-400">
         {{ currentPage === 'writer' ? '输出预览' : '范式分析结果' }}
       </span>
@@ -35,8 +35,8 @@
     </header>
 
     <!-- 主内容区 -->
-    <div class="flex-1 overflow-y-auto p-8 md:p-12">
-      <div class="max-w-3xl mx-auto min-h-[500px]">
+    <div class="flex-1 overflow-y-auto p-8 md:p-12 min-h-0">
+      <div class="max-w-3xl mx-auto pb-8">
         <!-- 写作页面内容 -->
         <div v-if="currentPage === 'writer'">
           <div v-if="!generatedContent && !isGenerating" class="h-full flex flex-col items-center justify-center text-slate-700 mt-20">