fix: harden real backend workflows and channel connections

src/apps/client/ClientSendPage.tsx

@@ -1,5 +1,5 @@
 import { useEffect, useMemo, useState } from 'react';
-import { Check, FileText, Plus, Search, Send, Trash2 } from 'lucide-react';
+import { Check, Download, FileText, Plus, Search, Send, Trash2 } from 'lucide-react';
 import { Button, DateTimeInput, Input, Modal, Select, Tag, Textarea } from '@/components/ui';
 import { clientApi, type ClientSmsApplication, type ClientSmsSignature, type ClientSmsTemplate, type ImportPreviewResponse, type SmsBatchTask } from '@/api/adminApi';
 
@@ -29,6 +29,7 @@ export function ClientSendPage() {
   const [recipients, setRecipients] = useState<Recipient[]>([{ id: '1', phone: '' }]);
   const [importContent, setImportContent] = useState('');
   const [importFileName, setImportFileName] = useState('');
+  const [importFileUrl, setImportFileUrl] = useState('');
   const [importPreview, setImportPreview] = useState<ImportPreviewResponse | null>(null);
   const [importLoading, setImportLoading] = useState(false);
   const [submittedRecord, setSubmittedRecord] = useState<SmsBatchTask | null>(null);
@@ -44,6 +45,12 @@ export function ClientSendPage() {
       .catch((reason: Error) => setError(reason.message || '短信发送基础数据加载失败'));
   }, []);
 
+  useEffect(() => () => {
+    if (importFileUrl) {
+      URL.revokeObjectURL(importFileUrl);
+    }
+  }, [importFileUrl]);
+
   const selectedSignature = useMemo(
     () => signatures.find((item) => item.id === signatureId),
     [signatures, signatureId],
@@ -133,10 +140,22 @@ export function ClientSendPage() {
       });
       setImportContent(content);
       setImportFileName(file.name);
+      setImportFileUrl((current) => {
+        if (current) {
+          URL.revokeObjectURL(current);
+        }
+        return URL.createObjectURL(file);
+      });
       setImportPreview(preview);
     } catch (reason) {
       setImportContent('');
       setImportFileName('');
+      setImportFileUrl((current) => {
+        if (current) {
+          URL.revokeObjectURL(current);
+        }
+        return '';
+      });
       setImportPreview(null);
       setError(reason instanceof Error ? reason.message : '导入预览失败');
     } finally {
@@ -294,7 +313,17 @@ export function ClientSendPage() {
                 <Button disabled={importLoading || !templateId} onClick={() => document.getElementById('sms-import-file')?.click()} variant="ghost">
                   {importLoading ? '解析中...' : '选择文件'}
                 </Button>
-                {importFileName ? <span>文件：{importFileName}</span> : null}
+                {importFileName ? (
+                  <span>
+                    文件：{importFileName}
+                    {importFileUrl ? (
+                      <a className="file-action-link" download={importFileName} href={importFileUrl}>
+                        <Download size={14} />
+                        下载
+                      </a>
+                    ) : null}
+                  </span>
+                ) : null}
                 {importPreview ? (
                   <div className="detail-grid">
                     <div><span>总行数</span><strong>{importPreview.totalRows}</strong></div>