fix(app): clean up i18n settings labels

packages/app/src/i18n/locales.test.ts

@@ -1,5 +1,10 @@
 import { describe, expect, it } from "vitest";
-import { LANGUAGE_OPTIONS, parseAppLanguage, resolveSupportedLocale } from "./locales";
+import {
+  LANGUAGE_OPTIONS,
+  formatLanguageOptionLabel,
+  parseAppLanguage,
+  resolveSupportedLocale,
+} from "./locales";
 
 describe("parseAppLanguage", () => {
   it("accepts system and all UN official language locales", () => {
@@ -32,6 +37,44 @@ describe("parseAppLanguage", () => {
   });
 });
 
+describe("formatLanguageOptionLabel", () => {
+  it("shows the native language name and English name in English UI", () => {
+    const arabic = LANGUAGE_OPTIONS.find((option) => option.value === "ar");
+    const spanish = LANGUAGE_OPTIONS.find((option) => option.value === "es");
+    const chinese = LANGUAGE_OPTIONS.find((option) => option.value === "zh-CN");
+
+    expect([
+      formatLanguageOptionLabel(arabic!, "en", "System"),
+      formatLanguageOptionLabel(spanish!, "en", "System"),
+      formatLanguageOptionLabel(chinese!, "en", "System"),
+    ]).toEqual(["العربية - Arabic", "Español - Spanish", "简体中文 - Simplified Chinese"]);
+  });
+
+  it("shows the native language name and Chinese name in Chinese UI", () => {
+    const arabic = LANGUAGE_OPTIONS.find((option) => option.value === "ar");
+    const english = LANGUAGE_OPTIONS.find((option) => option.value === "en");
+    const spanish = LANGUAGE_OPTIONS.find((option) => option.value === "es");
+
+    expect([
+      formatLanguageOptionLabel(arabic!, "zh-CN", "系统"),
+      formatLanguageOptionLabel(english!, "zh-CN", "系统"),
+      formatLanguageOptionLabel(spanish!, "zh-CN", "系统"),
+    ]).toEqual(["العربية - 阿拉伯语", "English - 英语", "Español - 西班牙语"]);
+  });
+
+  it("uses a single label when both language names match", () => {
+    const english = LANGUAGE_OPTIONS.find((option) => option.value === "en");
+
+    expect(formatLanguageOptionLabel(english!, "en", "System")).toBe("English");
+  });
+
+  it("uses the active-language name for System", () => {
+    const system = LANGUAGE_OPTIONS.find((option) => option.value === "system");
+
+    expect(formatLanguageOptionLabel(system!, "zh-CN", "系统")).toBe("系统");
+  });
+});
+
 describe("resolveSupportedLocale", () => {
   it("respects explicit language choices", () => {
     expect(resolveSupportedLocale("ar", ["en-US"])).toBe("ar");
@@ -44,11 +87,16 @@ describe("resolveSupportedLocale", () => {
 
   it("maps UN official system locales", () => {
     expect(resolveSupportedLocale("system", ["ar-EG"])).toBe("ar");
+    expect(resolveSupportedLocale("system", ["en-US"])).toBe("en");
     expect(resolveSupportedLocale("system", ["es-MX"])).toBe("es");
     expect(resolveSupportedLocale("system", ["fr-CA"])).toBe("fr");
     expect(resolveSupportedLocale("system", ["ru-RU"])).toBe("ru");
   });
 
+  it("keeps English when Spanish is a secondary system language", () => {
+    expect(resolveSupportedLocale("system", ["en-US", "es-GB"])).toBe("en");
+  });
+
   it("maps Chinese system locales to Simplified Chinese", () => {
     expect(resolveSupportedLocale("system", ["zh"])).toBe("zh-CN");
     expect(resolveSupportedLocale("system", ["zh-CN"])).toBe("zh-CN");