fix(mining-admin-web): fix audit logs page crash

- Use 'all' instead of empty string for SelectItem value (Radix requirement)
- Add null safety for items array with fallback to empty array
- Fix potential undefined access on data.items

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

frontend/mining-admin-web/src/app/(dashboard)/audit-logs/page.tsx

@@ -36,20 +36,22 @@ const actionLabels: Record<string, { label: string; className: string }> = {
 
 export default function AuditLogsPage() {
   const [page, setPage] = useState(1);
-  const [action, setAction] = useState<string>('');
+  const [action, setAction] = useState<string>('all');
   const [keyword, setKeyword] = useState('');
   const pageSize = 20;
 
-  const { data, isLoading } = useQuery({
+  const { data, isLoading, error } = useQuery({
     queryKey: ['audit-logs', page, action, keyword],
     queryFn: async () => {
       const response = await apiClient.get('/audit', {
-        params: { page, pageSize, action: action || undefined, keyword: keyword || undefined },
+        params: { page, pageSize, action: action === 'all' ? undefined : action, keyword: keyword || undefined },
       });
       return response.data.data as PaginatedResponse<AuditLog>;
     },
   });
 
+  const items = data?.items ?? [];
+
   return (
     <div className="space-y-6">
       <PageHeader title="审计日志" description="查看系统操作日志" />
@@ -71,7 +73,7 @@ export default function AuditLogsPage() {
                 <SelectValue placeholder="操作类型" />
               </SelectTrigger>
               <SelectContent>
-                <SelectItem value="">全部</SelectItem>
+                <SelectItem value="all">全部</SelectItem>
                 <SelectItem value="CREATE">创建</SelectItem>
                 <SelectItem value="UPDATE">更新</SelectItem>
                 <SelectItem value="DELETE">删除</SelectItem>
@@ -108,14 +110,14 @@ export default function AuditLogsPage() {
                     ))}
                   </TableRow>
                 ))
-              ) : data?.items.length === 0 ? (
+              ) : items.length === 0 ? (
                 <TableRow>
                   <TableCell colSpan={7} className="text-center py-8 text-muted-foreground">
                     暂无日志
                   </TableCell>
                 </TableRow>
               ) : (
-                data?.items.map((log) => {
+                items.map((log) => {
                   const actionInfo = actionLabels[log.action] || { label: log.action, className: '' };
                   return (
                     <TableRow key={log.id}>