feat: 集成n8n中文翻译

详细说明:
- 集成n8n-i18n-chinese项目的中文翻译文件
- 配置i18n系统支持中文界面
- 修改默认语言为zh-CN
- 修复凭证配置null数据问题

修改的文件:
- packages/frontend/@n8n/i18n/src/index.ts
- packages/frontend/@n8n/i18n/src/locales/zh-CN.json
- packages/frontend/editor-ui/src/components/CredentialEdit/CredentialConfig.vue

影响的功能:
- 整个n8n界面显示为中文
- 支持中英文切换
- 提升中国用户使用体验

n8n-n8n-1.109.2/packages/frontend/@n8n/i18n/src/index.ts

@@ -3,6 +3,7 @@ import type { INodeProperties, INodePropertyCollection, INodePropertyOptions } f
 import { createI18n } from 'vue-i18n';
 
 import englishBaseText from './locales/en.json';
+import chineseBaseText from './locales/zh-CN.json';
 import type { BaseTextKey, INodeTranslationHeaders } from './types';
 import {
 	deriveMiddleKey,
@@ -15,9 +16,12 @@ export * from './types';
 
 export const i18nInstance = createI18n({
 	legacy: false,
-	locale: 'en',
+	locale: 'zh-CN',
 	fallbackLocale: 'en',
-	messages: { en: englishBaseText },
+	messages: { 
+		en: englishBaseText,
+		'zh-CN': chineseBaseText
+	},
 	warnHtmlMessage: false,
 });
 
@@ -375,7 +379,7 @@ export class I18nClass {
 	};
 }
 
-const loadedLanguages = ['en'];
+const loadedLanguages = ['en', 'zh-CN'];
 
 async function setLanguage(language: string) {
 	i18nInstance.global.locale.value = language as 'en';

n8n-n8n-1.109.2/packages/frontend/editor-ui/src/components/CredentialEdit/CredentialConfig.vue

@@ -91,6 +91,8 @@ onBeforeMount(async () => {
 		props.credentialType.name,
 	);
 
+	if (!credTranslation) return;
+
 	addCredentialTranslation(
 		{ [props.credentialType.name]: credTranslation },
 		rootStore.defaultLocale,