fix: add progress indicator for checkpoint restore operation

Issue:
- Restore operation lacked visual feedback during long-running process
- Users couldn't tell if restore was in progress or completed
- No indication of which checkpoint was being restored

Solution:
- Added dedicated progress modal that appears immediately after clicking "恢复"
- Progress modal displays:
  * Large spinning loader animation
  * Clear "正在恢复检查点..." title
  * Checkpoint ID being restored
  * User guidance text: "此操作可能需要几分钟时间，请耐心等待..."

Benefits:
- Users clearly see restore operation is in progress
- Modal blocks interaction until operation completes
- Provides checkpoint ID for confirmation
- Improves user confidence during long operations

This ensures users understand the system is working and prevents confusion.

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

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

static/db_admin.html

@@ -1430,14 +1430,20 @@
         async function restoreCheckpoint(checkpointId) {
             closeDangerModal();
 
+            // 显示恢复进度模态框
+            showRestoreProgressModal(checkpointId);
+
             try {
                 const response = await fetch(`/fs-ai-asistant/api/workflow/lawrisk/admin/checkpoints/${checkpointId}/restore`, {
                     method: 'POST'
                 });
                 const data = await response.json();
 
+                // 关闭进度模态框
+                closeRestoreProgressModal();
+
                 if (data.success) {
-                    // 使用定时器延迟alert，确保modal已关闭
+                    // 显示成功消息
                     setTimeout(() => {
                         alert(`✅ 检查点恢复成功！\n\n恢复了 ${data.data.total_rows_restored} 行数据，覆盖了 ${data.data.tables_restored} 个表。`);
                     }, 100);
@@ -1448,12 +1454,44 @@
                     }, 100);
                 }
             } catch (error) {
+                closeRestoreProgressModal();
                 setTimeout(() => {
                     alert(`❌ 网络错误：${error.message}`);
                 }, 100);
             }
         }
 
+        // 显示恢复进度模态框
+        function showRestoreProgressModal(checkpointId) {
+            const modal = document.createElement('div');
+            modal.id = 'restoreProgressModal';
+            modal.className = 'modal show';
+            modal.innerHTML = `
+                <div class="modal-content" style="max-width: 450px; text-align: center; padding: 40px;">
+                    <div style="margin-bottom: 20px;">
+                        <div class="loading" style="width: 50px; height: 50px; border-width: 4px; margin: 0 auto;"></div>
+                    </div>
+                    <h3 style="color: #333; margin-bottom: 15px;">正在恢复检查点...</h3>
+                    <p style="color: #666; font-size: 14px; line-height: 1.6;">
+                        正在从备份恢复数据库<br>
+                        <strong>${checkpointId}</strong><br>
+                        <span style="color: #999; font-size: 12px; margin-top: 10px; display: block;">
+                            此操作可能需要几分钟时间，请耐心等待...
+                        </span>
+                    </p>
+                </div>
+            `;
+            document.body.appendChild(modal);
+        }
+
+        // 关闭恢复进度模态框
+        function closeRestoreProgressModal() {
+            const modal = document.getElementById('restoreProgressModal');
+            if (modal) {
+                modal.remove();
+            }
+        }
+
         // 删除检查点
         async function deleteCheckpoint(checkpointId) {
             if (!confirm(`确定要删除检查点 "${checkpointId}" 吗？此操作无法撤销。`)) {