🎨 简化存储管理界面，移除重复按钮

前端优化：
- 移除顶部的快速切换按钮
- 只保留下方详细的卡片式按钮
- 保留视觉指示器（进度条动画）
- 减少界面冗余，提升简洁性

视觉改进：
- 界面更加简洁清爽
- 避免重复的操作按钮
- 用户操作更加明确

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

frontend/app.html

@@ -1222,15 +1222,6 @@
 
             <div style="margin-top: 16px; background: white; border-radius: 12px; padding: 12px; border: 1px solid #e2e8f0;">
               <div style="display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 12px; align-items: center;">
-                <button
-                  class="btn"
-                  :class="storageType === 'local' ? 'btn-primary' : 'btn-secondary'"
-                  style="width: 100%; border-radius: 10px; padding: 12px; display: inline-flex; align-items: center; justify-content: center; gap: 8px; transition: all .3s;"
-                  :disabled="storageType === 'local' || storageSwitching"
-                  @click="switchStorage('local')">
-                  <i class="fas fa-hard-drive"></i>
-                  切换到本地
-                </button>
                 <div style="height: 4px; background: #e2e8f0; border-radius: 999px; position: relative; overflow: hidden;">
                   <div :style="{
                     position: 'absolute',
@@ -1242,15 +1233,6 @@
                     transition: 'left .35s ease'
                   }"></div>
                 </div>
-                <button
-                  class="btn"
-                  :class="storageType === 'sftp' ? 'btn-primary' : 'btn-secondary'"
-                  style="width: 100%; border-radius: 10px; padding: 12px; display: inline-flex; align-items: center; justify-content: center; gap: 8px; transition: all .3s;"
-                  :disabled="storageType === 'sftp' || storageSwitching"
-                  @click="switchStorage('sftp')">
-                  <i class="fas fa-server"></i>
-                  切换到 SFTP
-                </button>
               </div>
             </div>