💄 优化存储管理卡片布局对齐

前端优化：
- 使用 flexbox 布局确保卡片等高
- 按钮自动对齐到卡片底部
- 添加 align-items: stretch 确保卡片高度一致
- 使用 margin-top: auto 将按钮区域推到底部

视觉改进：
- 两个存储卡片高度保持一致
- 操作按钮在同一水平线上对齐
- 整体布局更加美观和协调

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

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

frontend/app.html

@@ -1254,8 +1254,8 @@
               </div>
             </div>
 
-            <div style="display: grid; grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); gap: 14px; margin-top: 14px;">
+            <div style="display: grid; grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); gap: 14px; margin-top: 14px; align-items: stretch;">
-              <div style="background: white; border: 1px solid #e2e8f0; border-radius: 12px; padding: 16px; box-shadow: 0 6px 20px rgba(0,0,0,0.04);">
+              <div style="background: white; border: 1px solid #e2e8f0; border-radius: 12px; padding: 16px; box-shadow: 0 6px 20px rgba(0,0,0,0.04); display: flex; flex-direction: column; height: 100%;">
                 <div style="display: flex; justify-content: space-between; align-items: center; margin-bottom: 10px;">
                   <div style="font-weight: 700; color: #0f172a; display: flex; gap: 8px; align-items: center;">
                     <i class="fas fa-hard-drive"></i> 本地存储
@@ -1275,12 +1275,14 @@
                     }"></div>
                   </div>
                 </div>
+                <div style="margin-top: auto;">
                   <button class="btn btn-primary" style="width: 100%; border-radius: 10px;" :disabled="storageType === 'local' || storageSwitching" @click="switchStorage('local')">
                     <i class="fas fa-bolt"></i> 用本地存储
                   </button>
                 </div>
+              </div>
 
-              <div style="background: white; border: 1px solid #e2e8f0; border-radius: 12px; padding: 16px; box-shadow: 0 6px 20px rgba(0,0,0,0.04);">
+              <div style="background: white; border: 1px solid #e2e8f0; border-radius: 12px; padding: 16px; box-shadow: 0 6px 20px rgba(0,0,0,0.04); display: flex; flex-direction: column; height: 100%;">
                 <div style="display: flex; justify-content: space-between; align-items: center; margin-bottom: 10px;">
                   <div style="font-weight: 700; color: #0f172a; display: flex; gap: 8px; align-items: center;">
                     <i class="fas fa-server"></i> SFTP 存储
@@ -1294,6 +1296,7 @@
                 <div v-else style="font-size: 13px; color: #b45309; background: #fff7ed; border: 1px dashed #fcd34d; padding: 10px; border-radius: 8px; margin-bottom: 10px;">
                   <i class="fas fa-exclamation-circle"></i> 先填写 SFTP 连接信息再切换
                 </div>
+                <div style="margin-top: auto;">
                   <button
                     class="btn"
                     :class="user?.has_ftp_config ? 'btn-primary' : 'btn-secondary'"
@@ -1310,6 +1313,7 @@
                   </div>
                 </div>
               </div>
+            </div>
 
             <div style="margin-top: 12px; padding: 10px 12px; background: #f1f5f9; border-radius: 10px; font-size: 13px; color: #475569;">
               <i class="fas fa-info-circle" style="color: #4b5fc9;"></i>