i18n(it): ship Italian

- Register it: catalog in index.js, LOCALES and LOCALE_NAMES (Italiano);
  it-IT, it-CH and other it tags select it.
- List it.json with the other catalogs in package-boundaries.json.
- docs/translations/it.md: style, plurals and glossary; Italian in the
  shipped lists of TRANSLATORS.md and CURRENT-STATE.md.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

src/i18n/i18n.test.mjs

@@ -35,6 +35,8 @@ test('normalizeLocale folds regional variants and rejects unshipped tags', () =>
   assert.equal(normalizeLocale(' RU '), 'ru');
   assert.equal(normalizeLocale('en_GB'), 'en');
   assert.equal(normalizeLocale('xx'), null);
+  assert.equal(normalizeLocale('it-IT'), 'it');
+  assert.equal(normalizeLocale('it_CH'), 'it');
   // Explicit script tags take precedence over regional defaults.
   assert.equal(normalizeLocale('zh'), 'zh-CN');
   assert.equal(normalizeLocale('zh-CN'), 'zh-CN');

src/i18n/index.js

@@ -17,11 +17,18 @@ import {
   writeStoredLocale,
 } from './locale.js';
 import es from './locales/es.json' with { type: 'json' };
+import it from './locales/it.json' with { type: 'json' };
 import ru from './locales/ru.json' with { type: 'json' };
 import zhCN from './locales/zh-CN.json' with { type: 'json' };
 import zhHant from './locales/zh-Hant.json' with { type: 'json' };
 
-const CATALOGS = Object.freeze({ es, ru, 'zh-CN': zhCN, 'zh-Hant': zhHant });
+const CATALOGS = Object.freeze({
+  es,
+  it,
+  ru,
+  'zh-CN': zhCN,
+  'zh-Hant': zhHant,
+});
 
 let currentLocale = DEFAULT_LOCALE;
 

src/i18n/locale.js

@@ -8,12 +8,20 @@ export const LOCALE_STORAGE_KEY = 'gev:locale:v1';
 export const DEFAULT_LOCALE = 'en';
 
 /** Shipped locales; order does not matter. Adding one: docs/TRANSLATORS.md. */
-export const LOCALES = Object.freeze(['en', 'es', 'ru', 'zh-CN', 'zh-Hant']);
+export const LOCALES = Object.freeze([
+  'en',
+  'es',
+  'it',
+  'ru',
+  'zh-CN',
+  'zh-Hant',
+]);
 
 /** Each locale named in its own language, for the selector. */
 export const LOCALE_NAMES = Object.freeze({
   en: 'English',
   es: 'Español',
+  it: 'Italiano',
   ru: 'Русский',
   'zh-CN': '中文（简体）',
   'zh-Hant': '中文（繁體）',

src/ui/localePicker.test.mjs

@@ -40,7 +40,7 @@ test('the current language comes first, the rest by their own names', () => {
         nativeNames: LOCALE_NAMES,
       }),
     ),
-    ['ru', 'en', 'es', 'zh-CN', 'zh-Hant'],
+    ['ru', 'en', 'es', 'it', 'zh-CN', 'zh-Hant'],
   );
   assert.deepEqual(
     codes(
@@ -50,7 +50,7 @@ test('the current language comes first, the rest by their own names', () => {
         nativeNames: LOCALE_NAMES,
       }),
     ),
-    ['es', 'en', 'ru', 'zh-CN', 'zh-Hant'],
+    ['es', 'en', 'it', 'ru', 'zh-CN', 'zh-Hant'],
   );
   assert.deepEqual(
     codes(
@@ -60,7 +60,7 @@ test('the current language comes first, the rest by their own names', () => {
         nativeNames: LOCALE_NAMES,
       }),
     ),
-    ['en', 'es', 'ru', 'zh-CN', 'zh-Hant'],
+    ['en', 'es', 'it', 'ru', 'zh-CN', 'zh-Hant'],
   );
   const rows = buildLocaleOptions({
     locales: MANY,