Fix: Improve message input handling with Shift+Enter support (#5129)

### What problem does this PR solve?

just resolve issue： [Improve message input handling with Shift+Enter
support](https://github.com/infiniflow/ragflow/issues/5116)
### Type of change

- [x] New Feature (non-breaking change which adds functionality)

---------

Co-authored-by: wenju.li <wenju.li@deepctr.cn>

web/src/components/message-input/index.tsx

@@ -35,6 +35,7 @@ import {
   useEffect,
   useRef,
   useState,
+  KeyboardEventHandler,
 } from 'react';
 import FileIcon from '../file-icon';
 import styles from './index.less';
@@ -155,6 +156,13 @@ const MessageInput = ({
     setFileList([]);
   }, [fileList, onPressEnter, isUploadingFile]);
 
+  const handleInputKeyDown: KeyboardEventHandler<HTMLTextAreaElement> = (e) => {
+    if (e.key === 'Enter' && !e.nativeEvent.shiftKey) {
+      e.preventDefault();
+      handlePressEnter();
+    }
+  };
+
   const handleRemove = useCallback(
     async (file: UploadFile) => {
       const ids = get(file, 'response.data', []);
@@ -202,13 +210,17 @@ const MessageInput = ({
 
   return (
     <Flex gap={20} vertical className={styles.messageInputWrapper}>
-      <Input
+      <Flex align="center" gap={8}>
+        <Input.TextArea
           size="large"
           placeholder={t('sendPlaceholder')}
           value={value}
           disabled={disabled}
           className={classNames({ [styles.inputWrapper]: fileList.length === 0 })}
-        suffix={
+          onKeyDown={handleInputKeyDown}
+          onChange={onInputChange}
+          autoSize={{ minRows: 1, maxRows: 6 }}
+        />
         <Space>
           {showUploadIcon && (
             <Upload
@@ -224,7 +236,7 @@ const MessageInput = ({
               <Button
                 type={'text'}
                 disabled={disabled}
-                  icon={<Paperclip></Paperclip>}
+                icon={<Paperclip />}
               ></Button>
             </Upload>
           )}
@@ -237,10 +249,7 @@ const MessageInput = ({
             {t('send')}
           </Button>
         </Space>
-        }
+      </Flex>
-        onPressEnter={handlePressEnter}
-        onChange={onInputChange}
-      />
 
       {fileList.length > 0 && (
         <List