1、后台界面/video-engines，添加修改需要增加可传图片和视频的数量

2、前台接口/credits/ratios，同步返回

video-gen-admin/src/pages/AdminVideoEngines.tsx

@@ -17,6 +17,9 @@ interface VideoEngine {
   supportedRatios: string[];
   supportedResolutions: string[];
   supportedDurations: number[];
+  maxDuration: number;
+  maxImageCount: number;
+  maxVideoCount: number;
   isActive: boolean;
   priority: number;
 }
@@ -66,6 +69,9 @@ const AdminVideoEngines: React.FC = () => {
         supported_ratios: JSON.stringify(values.supportedRatios || []),
         supported_resolutions: JSON.stringify(values.supportedResolutions || []),
         supported_durations: JSON.stringify(values.supportedDurations || []),
+        max_duration: values.maxDuration ?? 15,
+        max_image_count: values.maxImageCount ?? 5,
+        max_video_count: values.maxVideoCount ?? 2,
         is_active: values.isActive ?? true,
         priority: values.priority ?? 0,
       };
@@ -103,6 +109,9 @@ const AdminVideoEngines: React.FC = () => {
       form.resetFields();
       form.setFieldsValue({
         isActive: true, priority: 0,
+        maxDuration: 15,
+        maxImageCount: 5,
+        maxVideoCount: 2,
         supportedRatios: ['16:9', '4:3', '1:1', '3:4', '9:16', '21:9'],
         supportedResolutions: ['480p', '720p', '1080p'],
         supportedDurations: [4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15],
@@ -142,6 +151,14 @@ const AdminVideoEngines: React.FC = () => {
       title: '支持时长', dataIndex: 'supportedDurations', width: 120,
       render: (d: number[]) => <Tag color="orange">{d?.length ? `${Math.min(...d)}-${Math.max(...d)}s` : '-'}</Tag>,
     },
+    {
+      title: '最大图片', dataIndex: 'maxImageCount', width: 100,
+      render: (v: number) => <Tag color="purple">{v} 张</Tag>,
+    },
+    {
+      title: '最大视频', dataIndex: 'maxVideoCount', width: 100,
+      render: (v: number) => <Tag color="cyan">{v} 个</Tag>,
+    },
     {
       title: '状态', dataIndex: 'isActive', width: 80,
       render: (v: boolean) => <Tag color={v ? 'green' : 'default'}>{v ? '启用' : '停用'}</Tag>,
@@ -234,6 +251,17 @@ const AdminVideoEngines: React.FC = () => {
               } />
             </Form.Item>
           </div>
+          <div style={{ display: 'flex', gap: 16 }}>
+            <Form.Item name="maxDuration" label="最大时长(秒)" style={{ flex: 1 }}>
+              <Input type="number" size="large" />
+            </Form.Item>
+            <Form.Item name="maxImageCount" label="最大图片数量" style={{ flex: 1 }}>
+              <Input type="number" size="large" />
+            </Form.Item>
+            <Form.Item name="maxVideoCount" label="最大视频数量" style={{ flex: 1 }}>
+              <Input type="number" size="large" />
+            </Form.Item>
+          </div>
           <div style={{ display: 'flex', gap: 16 }}>
             <Form.Item name="priority" label="优先级">
               <Select size="large" options={[