fix: address code review findings for i18n

- Fix detectLanguage() to follow POSIX priority: LC_ALL > LC_MESSAGES > LANG
- Fix Chinese format.resetsIn from broken wrap-around grammar to prefix form
- Fix loadConfig() to call mergeConfig({}) when no config file exists,
  ensuring detectLanguage() runs for auto-detection
- Add setLanguage('en') guard to render.test.js for locale-independent tests
- Add dedicated i18n test suite (tests/i18n.test.js) covering t(),
  detectLanguage(), and mergeConfig language handling

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/config.ts

@@ -96,8 +96,9 @@ export interface HudConfig {
 }
 
 export function detectLanguage(): Language {
+  // POSIX priority: LC_ALL overrides everything, then LC_MESSAGES, then LANG
   const envLang =
-    process.env.LANG || process.env.LC_ALL || process.env.LC_MESSAGES || "";
+    process.env.LC_ALL || process.env.LC_MESSAGES || process.env.LANG || "";
   if (envLang.startsWith("zh")) return "zh";
   return "en";
 }
@@ -458,13 +459,13 @@ export async function loadConfig(): Promise<HudConfig> {
 
   try {
     if (!fs.existsSync(configPath)) {
-      return DEFAULT_CONFIG;
+      return mergeConfig({});
     }
 
     const content = fs.readFileSync(configPath, "utf-8");
     const userConfig = JSON.parse(content) as Partial<HudConfig>;
     return mergeConfig(userConfig);
   } catch {
-    return DEFAULT_CONFIG;
+    return mergeConfig({});
   }
 }

src/i18n/zh.ts

@@ -14,7 +14,7 @@ export const zh: Messages = {
 
   // Format
   "format.resets": "重置于",
-  "format.resetsIn": "将在...后重置",
+  "format.resetsIn": "重置剩余",
   "format.in": "输入",
   "format.cache": "缓存",
   "format.out": "输出",

tests/i18n.test.js

@@ -0,0 +1,126 @@
+import { test } from "node:test";
+import assert from "node:assert/strict";
+import { setLanguage, getLanguage, t } from "../dist/i18n/index.js";
+import { detectLanguage, mergeConfig } from "../dist/config.js";
+
+test("t() returns English strings by default", () => {
+  setLanguage("en");
+  assert.equal(t("label.context"), "Context");
+  assert.equal(t("label.usage"), "Usage");
+  assert.equal(t("label.approxRam"), "Approx RAM");
+  assert.equal(t("status.limitReached"), "Limit reached");
+  assert.equal(t("status.allTodosComplete"), "All todos complete");
+});
+
+test("t() returns Chinese strings when language is zh", () => {
+  setLanguage("zh");
+  assert.equal(t("label.context"), "上下文");
+  assert.equal(t("label.usage"), "用量");
+  assert.equal(t("label.approxRam"), "内存");
+  assert.equal(t("label.rules"), "规则");
+  assert.equal(t("label.hooks"), "钩子");
+  assert.equal(t("status.limitReached"), "已达上限");
+  assert.equal(t("status.allTodosComplete"), "全部完成");
+  assert.equal(t("format.in"), "输入");
+  assert.equal(t("format.cache"), "缓存");
+  assert.equal(t("format.out"), "输出");
+  // Restore
+  setLanguage("en");
+});
+
+test("setLanguage and getLanguage round-trip", () => {
+  setLanguage("zh");
+  assert.equal(getLanguage(), "zh");
+  setLanguage("en");
+  assert.equal(getLanguage(), "en");
+});
+
+test("detectLanguage respects LC_ALL over LANG (POSIX priority)", () => {
+  const origLang = process.env.LANG;
+  const origLcAll = process.env.LC_ALL;
+  const origLcMsg = process.env.LC_MESSAGES;
+
+  try {
+    process.env.LANG = "en_US.UTF-8";
+    process.env.LC_ALL = "zh_CN.UTF-8";
+    delete process.env.LC_MESSAGES;
+    assert.equal(detectLanguage(), "zh");
+
+    process.env.LC_ALL = "en_US.UTF-8";
+    process.env.LANG = "zh_CN.UTF-8";
+    assert.equal(detectLanguage(), "en");
+
+    delete process.env.LC_ALL;
+    assert.equal(detectLanguage(), "zh");
+  } finally {
+    process.env.LANG = origLang;
+    process.env.LC_ALL = origLcAll;
+    process.env.LC_MESSAGES = origLcMsg;
+  }
+});
+
+test("detectLanguage returns en for unknown locales", () => {
+  const origLang = process.env.LANG;
+  const origLcAll = process.env.LC_ALL;
+  const origLcMsg = process.env.LC_MESSAGES;
+
+  try {
+    delete process.env.LC_ALL;
+    delete process.env.LC_MESSAGES;
+    process.env.LANG = "fr_FR.UTF-8";
+    assert.equal(detectLanguage(), "en");
+
+    process.env.LANG = "C";
+    assert.equal(detectLanguage(), "en");
+
+    delete process.env.LANG;
+    assert.equal(detectLanguage(), "en");
+  } finally {
+    process.env.LANG = origLang;
+    process.env.LC_ALL = origLcAll;
+    process.env.LC_MESSAGES = origLcMsg;
+  }
+});
+
+test("mergeConfig uses detectLanguage when no language specified", () => {
+  const origLcAll = process.env.LC_ALL;
+  const origLang = process.env.LANG;
+  const origLcMsg = process.env.LC_MESSAGES;
+
+  try {
+    process.env.LC_ALL = "zh_CN.UTF-8";
+    delete process.env.LC_MESSAGES;
+    const config = mergeConfig({});
+    assert.equal(config.language, "zh");
+  } finally {
+    process.env.LC_ALL = origLcAll;
+    process.env.LANG = origLang;
+    process.env.LC_MESSAGES = origLcMsg;
+  }
+});
+
+test("mergeConfig preserves explicit language from config", () => {
+  const config = mergeConfig({ language: "zh" });
+  assert.equal(config.language, "zh");
+
+  const config2 = mergeConfig({ language: "en" });
+  assert.equal(config2.language, "en");
+});
+
+test("mergeConfig falls back to detection for invalid language", () => {
+  const origLcAll = process.env.LC_ALL;
+  const origLang = process.env.LANG;
+  const origLcMsg = process.env.LC_MESSAGES;
+
+  try {
+    delete process.env.LC_ALL;
+    delete process.env.LC_MESSAGES;
+    process.env.LANG = "C";
+    const config = mergeConfig({ language: "invalid" });
+    assert.equal(config.language, "en");
+  } finally {
+    process.env.LC_ALL = origLcAll;
+    process.env.LANG = origLang;
+    process.env.LC_MESSAGES = origLcMsg;
+  }
+});