i18n(zh-CN): complete and ship Simplified Chinese

- Translate the remaining 910 strings and review the whole catalog (meaning,
  terms, punctuation, label length) against the screens.
- Register zh-CN: any zh tag maps to it except Traditional ones (Hant, TW,
  HK, MO), which keep English until a Traditional catalog ships.
- Hemisphere letters get their own context so the HUD sector line reads
  21.33N, not a compass word; the Bhote Koshi imagery dates follow
  year-first languages (2021年10月16日).
- cjk.css: tight tracking for Chinese text and a 9px floor on the dock voice
  labels and layer buttons; Latin HUD readouts keep their look.
- docs/translations/zh-CN.md: style, plurals and glossary.

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

src/data/bhoteKoshiEvent.js

@@ -412,14 +412,18 @@ const IMAGERY_LABEL_NAMES = Object.freeze([
   [/^(\d{4}) POST-EVENT$/, msg('{year} POST-EVENT')],
 ]);
 
-/** Day, short month and year in the active language: 16 OCT 2021, 16 ОКТ. 2021. */
+/** Day, short month and year in the active language: 16 OCT 2021, 16 ОКТ. 2021, 2021年10月16日. */
 function imageryDateText(observedAt) {
   const match = /^(\d{4})-(\d{2})-(\d{2})$/.exec(String(observedAt || ''));
   if (!match) return '';
   const date = new Date(Date.UTC(+match[1], +match[2] - 1, +match[3]));
   if (Number.isNaN(date.getTime())) return '';
   const part = (options) => formatDate(date, { timeZone: 'UTC', ...options });
-  return `${part({ day: 'numeric' })} ${part({ month: 'short' })} ${part({ year: 'numeric' })}`.toUpperCase();
+  const year = part({ year: 'numeric' });
+  // Year-first languages (2021年10月16日) keep their own order and units.
+  const whole = part({ day: 'numeric', month: 'short', year: 'numeric' });
+  if (whole.startsWith(year)) return whole;
+  return `${part({ day: 'numeric' })} ${part({ month: 'short' })} ${year}`.toUpperCase();
 }
 
 /**
@@ -1029,7 +1033,7 @@ function createPanel(event, handlers) {
       <span>${escapeMarkup(t('GEOLOCATIONS · {credit}', { credit: 'GEO GEORGE SHADRACH' }))}</span>
       <button type="button" data-action="geolocation-map">${escapeMarkup(t('↗ OPEN PUBLIC MAP'))}</button>
     </div>
-    <p class="bhote-event-caveat"><span data-role="caveat"></span><span data-role="imagery-cloud-note"> ${escapeMarkup(t('Clouds are preserved from the source imagery.'))}</span></p>
+    <p class="bhote-event-caveat"><span data-role="caveat"></span><span data-role="imagery-cloud-note">${escapeMarkup(t(' Clouds are preserved from the source imagery.'))}</span></p>
   `;
 
   const refs = collectPanelReferences(panel);

src/hudLocalityFormat.js

@@ -35,7 +35,16 @@ export const LOCALIZED_LOCALITY = Object.freeze({
     }),
   sector: ({ latDeg, lonDeg }) =>
     t('SECTOR {lat} {lon}', {
-      lat: hudCoordinate(latDeg, t('N'), t('S')),
-      lon: hudCoordinate(lonDeg, t('E'), t('W')),
+      // Hemisphere letters, not compass words: 21.33N, never 21.33北.
+      lat: hudCoordinate(
+        latDeg,
+        t('N', { context: 'hemisphere' }),
+        t('S', { context: 'hemisphere' }),
+      ),
+      lon: hudCoordinate(
+        lonDeg,
+        t('E', { context: 'hemisphere' }),
+        t('W', { context: 'hemisphere' }),
+      ),
     }),
 });

src/i18n/i18n.test.mjs

@@ -35,6 +35,12 @@ 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);
+  // Simplified Chinese by default; Traditional tags wait for zh-TW.
+  assert.equal(normalizeLocale('zh'), 'zh-CN');
+  assert.equal(normalizeLocale('zh-CN'), 'zh-CN');
+  assert.equal(normalizeLocale('zh-Hans-SG'), 'zh-CN');
+  assert.equal(normalizeLocale('zh-TW'), null);
+  assert.equal(normalizeLocale('zh-Hant-HK'), null);
   assert.equal(normalizeLocale(undefined), null);
 });
 

src/i18n/index.js

@@ -18,8 +18,9 @@ import {
 } from './locale.js';
 import es from './locales/es.json' with { type: 'json' };
 import ru from './locales/ru.json' with { type: 'json' };
+import zhCN from './locales/zh-CN.json' with { type: 'json' };
 
-const CATALOGS = Object.freeze({ es, ru });
+const CATALOGS = Object.freeze({ es, ru, 'zh-CN': zhCN });
 
 let currentLocale = DEFAULT_LOCALE;
 

src/i18n/locale.js

@@ -8,25 +8,32 @@ 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']);
+export const LOCALES = Object.freeze(['en', 'es', 'ru', 'zh-CN']);
 
 /** Each locale named in its own language, for the selector. */
 export const LOCALE_NAMES = Object.freeze({
   en: 'English',
   es: 'Español',
   ru: 'Русский',
+  'zh-CN': '简体中文',
 });
 
 /** Right-to-left locales. */
 const RTL_LOCALES = Object.freeze([]);
 
 /**
- * Map any language tag to a shipped locale: 'ru-RU' and 'RU' → 'ru'.
+ * Map any language tag to a shipped locale: 'ru-RU' and 'RU' → 'ru',
+ * 'zh', 'zh-CN' and 'zh-Hans-SG' → 'zh-CN'.
  * @returns {string|null}
  */
 export function normalizeLocale(candidate) {
   if (typeof candidate !== 'string') return null;
-  const primary = candidate.trim().toLowerCase().split(/[-_]/)[0];
+  const [primary, ...rest] = candidate.trim().toLowerCase().split(/[-_]/);
+  // Traditional Chinese readers are not given Simplified: no zh-TW yet.
+  if (primary === 'zh')
+    return rest.some((part) => ['hant', 'tw', 'hk', 'mo'].includes(part))
+      ? null
+      : 'zh-CN';
   return LOCALES.includes(primary) ? primary : null;
 }
 

src/i18n/locales/es.json

@@ -1096,7 +1096,7 @@
   "FIELD REPORTS · {count}": "INFORMES DE CAMPO · {count}",
   "GEOLOCATIONS · {credit}": "GEOLOCALIZACIONES · {credit}",
   "↗ OPEN PUBLIC MAP": "↗ ABRIR MAPA PÚBLICO",
-  "Clouds are preserved from the source imagery.": "Las nubes provienen de las imágenes de origen.",
+  " Clouds are preserved from the source imagery.": " Las nubes provienen de las imágenes de origen.",
   "Show the Nepal context callout without a border or country fill": "Muestra la etiqueta de contexto de Nepal sin frontera ni relleno del país",
   "Introduce Nepal, draw its border, then reveal the Bhote Koshi incident": "Presenta Nepal, dibuja su frontera y luego revela el incidente del Bhote Koshi",
   "CITIES": "CIUDADES",
@@ -2890,5 +2890,9 @@
   "USB work abandoned after a stalled transfer": "Trabajo USB cancelado tras una transferencia bloqueada",
   "SDR decoder did not start; receiver stopped": "El decodificador SDR no arrancó; receptor detenido",
   "SDR decoder stopped responding; receiver stopped": "El decodificador SDR dejó de responder; receptor detenido",
-  "SDR decoder fell behind; receiver stopped": "El decodificador SDR se quedó atrás; receptor detenido"
+  "SDR decoder fell behind; receiver stopped": "El decodificador SDR se quedó atrás; receptor detenido",
+  "hemisphere|N": "N",
+  "hemisphere|S": "S",
+  "hemisphere|E": "E",
+  "hemisphere|W": "O"
 }

src/i18n/locales/ru.json

@@ -1110,7 +1110,7 @@
   "FIELD REPORTS · {count}": "СООБЩЕНИЯ С МЕСТА · {count}",
   "GEOLOCATIONS · {credit}": "ГЕОЛОКАЦИИ · {credit}",
   "↗ OPEN PUBLIC MAP": "↗ ОТКРЫТЬ ПУБЛИЧНУЮ КАРТУ",
-  "Clouds are preserved from the source imagery.": "Облака оставлены такими, как на исходных снимках.",
+  " Clouds are preserved from the source imagery.": " Облака оставлены такими, как на исходных снимках.",
   "Show the Nepal context callout without a border or country fill": "Показать выноску с контекстом Непала без границы и заливки страны",
   "Introduce Nepal, draw its border, then reveal the Bhote Koshi incident": "Представить Непал, нарисовать его границу, затем показать инцидент на Bhote Koshi",
   "CITIES": "ГОРОДА",
@@ -2957,5 +2957,9 @@
   "USB work abandoned after a stalled transfer": "Работа с USB прервана: передача данных зависла",
   "SDR decoder did not start; receiver stopped": "Декодер SDR не запустился; приёмник остановлен",
   "SDR decoder stopped responding; receiver stopped": "Декодер SDR перестал отвечать; приёмник остановлен",
-  "SDR decoder fell behind; receiver stopped": "Декодер SDR не успевает; приёмник остановлен"
+  "SDR decoder fell behind; receiver stopped": "Декодер SDR не успевает; приёмник остановлен",
+  "hemisphere|N": "С",
+  "hemisphere|S": "Ю",
+  "hemisphere|E": "В",
+  "hemisphere|W": "З"
 }

src/i18n/same-as-english.json

@@ -98,6 +98,9 @@
     "fire confidence|nominal",
     "ft",
     "hPa",
+    "hemisphere|E",
+    "hemisphere|N",
+    "hemisphere|S",
     "installation class|BASE",
     "km",
     "km/h",
@@ -133,5 +136,60 @@
     "REC",
     "VS",
     "WHOT/BHOT"
+  ],
+  "zh-CN": [
+    "1090 MHz",
+    "978 MHz UAT",
+    "AIS: --",
+    "AIS: {name}",
+    "BRG {value}°",
+    "BRG —",
+    "CAL {value}",
+    "CAL · {badge}",
+    "CCTV",
+    "CRS {value}°",
+    "CRT",
+    "FLIR",
+    "FOV",
+    "FOV {value}°",
+    "FT",
+    "GEO",
+    "HDG",
+    "HDG {value}°",
+    "House",
+    "Ironbow",
+    "KTS",
+    "Landsat 8/9",
+    "MM",
+    "NVG",
+    "REC",
+    "SRC {value}",
+    "Sentinel-2",
+    "Techno",
+    "Trance",
+    "USB {rate} msg/s",
+    "WHOT/BHOT",
+    "dB",
+    "ft",
+    "hPa",
+    "hemisphere|E",
+    "hemisphere|N",
+    "hemisphere|S",
+    "hemisphere|W",
+    "km",
+    "km/h",
+    "kt",
+    "kts",
+    "mph",
+    "{city} CCTV",
+    "{rate} msg/s",
+    "{source} HTTP {status}",
+    "{speed} kn",
+    "{type}  SPD: {speed}  HDG: {heading}",
+    "{value} KM",
+    "{value} KM/S",
+    "ΔE",
+    "ΔN",
+    "▲ {frp} MW"
   ]
 }

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'],
+    ['ru', 'en', 'es', 'zh-CN'],
   );
   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'],
+    ['es', 'en', 'ru', 'zh-CN'],
   );
   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'],
+    ['en', 'es', 'ru', 'zh-CN'],
   );
   const rows = buildLocaleOptions({
     locales: MANY,
@@ -263,7 +263,7 @@ test('keyboard model: open on the current language, move, choose, close', () =>
   assert.deepEqual(model.keydown({ key: 'ArrowDown' }), { handled: true });
   assert.equal(model.activeOption.code, 'en');
   model.keydown({ key: 'End' });
-  assert.equal(model.activeOption.code, 'es');
+  assert.equal(model.activeOption.code, 'zh-CN');
   model.keydown({ key: 'Home' });
   assert.equal(model.activeOption.code, 'ru');
   model.keydown({ key: 'ArrowUp' });

src/ui/styles/cjk.css

@@ -0,0 +1,29 @@
+/* Chinese text. The UI sets Latin capitals with wide tracking; Chinese set
+   that way falls apart into single glyphs, so its tracking stays tight. The
+   intel HUD readouts (codes, coordinates) and text kept in English on purpose
+   (translate="no", and whatever holds it) keep the Latin look. */
+html:lang(zh)
+  body
+  :not(
+    #intel-hud,
+    #intel-hud *,
+    [translate='no'],
+    [translate='no'] *,
+    :has([translate='no'])
+  ) {
+  letter-spacing: 0.02em !important;
+}
+
+/* Below about 9px a Chinese glyph blurs: lift the dock's voice labels and the
+   panel layer buttons to that floor. */
+html:lang(zh) #command-dock .gev-mic-label,
+html:lang(zh) #command-dock #gev-voice-detail,
+html:lang(zh) .gev-voice-tier-btn,
+html:lang(zh) .panel-layer-toggle {
+  font-size: 9px;
+}
+
+/* A two-glyph button label must not break between its glyphs. */
+html:lang(zh) .pp-mode-btn {
+  white-space: nowrap;
+}