✨ feat(i18n): 完善多模块多语言适配与发版验证

扩展前后端多语言文案与共享词典。增加多模块 i18n 回归测试与 guard。收口外部 SQL 菜单和弹窗多语言文案。

frontend/src/components/SidebarV2GroupFallback.i18n.test.ts

@@ -0,0 +1,36 @@
+import { readFileSync } from 'node:fs';
+import { describe, expect, it } from 'vitest';
+
+const sidebarSource = readFileSync(new URL('./Sidebar.tsx', import.meta.url), 'utf8');
+const sidebarV2UtilsSource = readFileSync(new URL('./sidebarV2Utils.ts', import.meta.url), 'utf8');
+
+const locales = ['zh-CN', 'zh-TW', 'en-US', 'ja-JP', 'de-DE', 'ru-RU'] as const;
+const requiredKeys = [
+  'connection.sidebar.group.untitled',
+  'connection.sidebar.group.badge',
+];
+
+describe('Sidebar v2 connection group fallback i18n', () => {
+  it('localizes v2 connection group fallback names and badges', () => {
+    [
+      "name: tag.name || '未命名分组'",
+      "fallback = '组'",
+    ].forEach((snippet) => {
+      expect(sidebarSource).not.toContain(snippet);
+      expect(sidebarV2UtilsSource).not.toContain(snippet);
+    });
+
+    expect(sidebarSource).toContain("tag.name || t('connection.sidebar.group.untitled')");
+    expect(sidebarSource).toContain("fallback = t('connection.sidebar.group.badge')");
+    expect(sidebarV2UtilsSource).toContain("fallback = t('connection.sidebar.group.badge')");
+  });
+
+  it('keeps v2 connection group fallback keys available in every locale', () => {
+    locales.forEach((locale) => {
+      const catalog = JSON.parse(readFileSync(new URL(`../../../shared/i18n/${locale}.json`, import.meta.url), 'utf8')) as Record<string, string>;
+      requiredKeys.forEach((key) => {
+        expect(catalog[key], `${locale}:${key}`).toBeTruthy();
+      });
+    });
+  });
+});