🐛 fix(ChatInput): add missing MaxTokens setting to params popover (#11412)

The MaxTokens setting was missing from the ChatInput ActionBar params
popover after UI refactoring. This adds:
- Enable MaxTokens toggle switch
- MaxTokens slider (0-32000) that appears when enabled

Fixes #11375

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

src/features/ChatInput/ActionBar/Params/Controls.tsx

@@ -1,6 +1,6 @@
-import { Form, type FormItemProps, Tag } from '@lobehub/ui';
+import { Form, type FormItemProps, SliderWithInput, Tag } from '@lobehub/ui';
 import { Checkbox, Flexbox } from '@lobehub/ui';
-import { Form as AntdForm } from 'antd';
+import { Form as AntdForm, Switch } from 'antd';
 import { createStaticStyles } from 'antd-style';
 import { debounce } from 'es-toolkit/compat';
 import isEqual from 'fast-deep-equal';
@@ -151,6 +151,7 @@ const Controls = memo<ControlsProps>(({ setUpdating }) => {
   const config = useAgentStore((s) => agentByIdSelectors.getAgentConfigById(agentId)(s), isEqual);
   const [form] = Form.useForm();
 
+  const enableMaxTokens = AntdForm.useWatch(['chatConfig', 'enableMaxTokens'], form);
   const { frequency_penalty, presence_penalty, temperature, top_p } = config.params ?? {};
 
   const lastValuesRef = useRef<Record<ParamKey, number | undefined>>({
@@ -289,6 +290,40 @@ const Controls = memo<ControlsProps>(({ setUpdating }) => {
     } satisfies FormItemProps;
   });
 
+  // MaxTokens items
+  const maxTokensItems: FormItemProps[] = [
+    {
+      children: <Switch />,
+      label: (
+        <Flexbox align={'center'} className={styles.label} gap={8} horizontal>
+          {t('settingModel.enableMaxTokens.title')}
+        </Flexbox>
+      ),
+      name: ['chatConfig', 'enableMaxTokens'],
+      tag: 'max_tokens',
+      valuePropName: 'checked',
+    },
+    ...(enableMaxTokens
+      ? [
+          {
+            children: (
+              <SliderWithInput max={32_000} min={0} step={100} unlimitedInput />
+            ),
+            label: (
+              <Flexbox align={'center'} className={styles.label} gap={8} horizontal>
+                {t('settingModel.maxTokens.title')}
+                <InfoTooltip title={t('settingModel.maxTokens.desc')} />
+              </Flexbox>
+            ),
+            name: ['params', 'max_tokens'],
+            tag: 'max_tokens',
+          } satisfies FormItemProps,
+        ]
+      : []),
+  ];
+
+  const allItems = [...baseItems, ...maxTokensItems];
+
   return (
     <Form
       form={form}
@@ -296,11 +331,11 @@ const Controls = memo<ControlsProps>(({ setUpdating }) => {
       itemMinWidth={220}
       items={
         mobile
-          ? baseItems
-          : baseItems.map(({ tag, ...item }) => ({
-            ...item,
-            desc: <Tag size={'small'}>{tag}</Tag>,
-          }))
+          ? allItems
+          : allItems.map(({ tag, ...item }) => ({
+              ...item,
+              desc: <Tag size={'small'}>{tag}</Tag>,
+            }))
       }
       itemsType={'flat'}
       onValuesChange={handleValuesChange}