Feat: Limit the iteration start node to only be the source node #4242 (#4260)

### What problem does this PR solve?

Feat: Limit the iteration start node to only be the source node #4242

### Type of change


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

web/src/locales/en.ts

         minus: 'Minus',
         semicolon: 'Semicolon',
       },
+      addVariable: 'Add variable',
+      variableSettings: 'Variable settings',
+      globalVariables: 'Global variables',
     },
     footer: {
       profile: 'All rights reserved @ React',

web/src/locales/zh-traditional.ts

         minus: '減號',
         semicolon: '分號',
       },
+      addVariable: '新增變數',
+      variableSettings: '變數設定',
     },
     footer: {
       profile: '“保留所有權利 @ react”',

web/src/locales/zh.ts

         minus: '减号',
         semicolon: '分号',
       },
+      addVariable: '新增变量',
+      variableSettings: '变量设置',
     },
     footer: {
       profile: 'All rights reserved @ React',

web/src/pages/flow/canvas/edge/index.tsx

   };
 
   // highlight the nodes that the workflow passes through
-  // const queryClient = useQueryClient();
-  // const flowDetail = queryClient.getQueryData<IFlow>(['flowDetail']);
   const { data: flowDetail } = useFetchFlow();
 
   const graphPath = useMemo(() => {

web/src/pages/flow/canvas/node/iteration-node.tsx

         isConnectable={isConnectable}
         className={styles.handle}
         style={RightHandleStyle}
+        isConnectableEnd={false}
       ></Handle>
       <div>
         <ListRestart className="size-7" />

web/src/pages/flow/form/begin-form/paramater-modal.tsx

 import { Form, Input, Modal, Select, Switch } from 'antd';
 import { DefaultOptionType } from 'antd/es/select';
 import { useEffect, useMemo } from 'react';
+import { useTranslation } from 'react-i18next';
 import { BeginQueryType, BeginQueryTypeIconMap } from '../../constant';
 import { BeginQuery } from '../../interface';
 import BeginDynamicOptions from './begin-dynamic-options';
   initialValue: BeginQuery;
   otherThanCurrentQuery: BeginQuery[];
 }) => {
+  const { t } = useTranslation();
   const [form] = Form.useForm();
   const options = useMemo(() => {
     return Object.values(BeginQueryType).reduce<DefaultOptionType[]>(
 
   return (
     <Modal
-      title="Begin query"
+      title={t('flow.variableSettings')}
       open={visible}
       onOk={onOk}
       onCancel={hideModal}

web/src/pages/flow/form/components/dynamic-input-variable.tsx

               icon={<PlusOutlined />}
               className={styles.addButton}
             >
-              {t('flow.addItem')}
+              {t('flow.addVariable')}
             </Button>
           </Form.Item>
         </>