i18n: generate zh-Hant from zh-CN

zh-Hant is the zh-CN text in Traditional characters, but contributors
still translated it by hand from `--missing zh-Hant`, and a model asked
for Traditional Chinese writes Taiwan vocabulary (影片, 伺服器, 載入).

`npm run i18n -- --zh-hant` now rewrites zh-Hant.json from zh-CN.json
with OpenCC s2tw (opencc-js 1.4.2, cn -> tw, characters only), then the
fixed list of characters it picks wrongly. The check that `npm test`
runs fails when zh-Hant differs from that conversion, naming the key,
and `--missing zh-Hant` points to the command instead of printing a
template.

The conversion reproduces every one of the 3346 entries on main. 25
keys were out of zh-CN order and move; no value changes.

The converter loads on first use, so a copy of the script without
node_modules (stale-index.test.mjs) still extracts messages.

src/i18n/catalog.test.mjs

@@ -3,13 +3,16 @@ import assert from 'node:assert/strict';
 
 import {
   checkCatalog,
+  checkZhHant,
   extractMessages,
   findUnmarked,
   markedTemplate,
   readCatalog,
   shippedLocales,
+  toZhHant,
   unmarkedMarkup,
   unmarkedScript,
+  zhHantCatalog,
 } from '../../scripts/i18n.mjs';
 import { LOCALES } from './locale.js';
 
@@ -36,6 +39,59 @@ for (const locale of shippedLocales()) {
   });
 }
 
+test('zh-Hant is zh-CN converted to Traditional characters (npm run i18n -- --zh-hant)', () => {
+  assert.deepEqual(
+    checkZhHant(readCatalog('zh-CN'), readCatalog('zh-Hant')),
+    [],
+  );
+});
+
+test('toZhHant converts characters, not vocabulary, and fixes what s2tw picks wrongly', () => {
+  // s2twp would write 影片, 伺服器 and 載入; zh-Hant keeps the zh-CN words.
+  assert.equal(toZhHant('视频'), '視頻');
+  assert.equal(toZhHant('服务器'), '服務器');
+  assert.equal(toZhHant('加载'), '加載');
+  assert.equal(toZhHant('50 年历史'), '50 年歷史');
+  assert.equal(toZhHant('发布于 {date}'), '發布於 {date}');
+  assert.equal(toZhHant('1 周/秒'), '1 週/秒');
+});
+
+test('checkZhHant names each entry that is not the conversion of zh-CN', () => {
+  const zhCN = {
+    Video: '视频',
+    Server: '服务器',
+    '{count} ships': { other: '{count} 艘船' },
+  };
+  const generated = zhHantCatalog(zhCN);
+  assert.deepEqual(generated, {
+    Video: '視頻',
+    Server: '服務器',
+    '{count} ships': { other: '{count} 艘船' },
+  });
+  assert.deepEqual(checkZhHant(zhCN, generated), []);
+
+  const fix =
+    'zh-Hant is generated: edit zh-CN, then run npm run i18n -- --zh-hant';
+  const { Server, ...withoutServer } = generated;
+  assert.deepEqual(
+    checkZhHant(zhCN, {
+      ...withoutServer,
+      Video: '影片',
+      '{count} ships': { other: '{count} 艘船隻' },
+      Extra: '多餘',
+    }),
+    [
+      `"Video" is "影片", not zh-CN converted ("視頻"). ${fix}`,
+      `"Server" is in zh-CN but not here. ${fix}`,
+      `"{count} ships" is {"other":"{count} 艘船隻"}, not zh-CN converted ({"other":"{count} 艘船"}). ${fix}`,
+      `"Extra" is not in zh-CN. ${fix}`,
+    ],
+  );
+  assert.deepEqual(checkZhHant(zhCN, { Server, ...withoutServer }), [
+    'entries leave the zh-CN order at "Video": run npm run i18n -- --zh-hant',
+  ]);
+});
+
 test('every UI string is marked for translation or kept on purpose (npm run i18n)', () => {
   assert.deepEqual(
     findUnmarked().map(({ where, text }) => `${where}  ${text}`),

src/i18n/locales/zh-Hant.json

@@ -612,6 +612,7 @@
   "Cyclone advisories unavailable": "氣旋公告不可用",
   "Cyclone data unavailable": "氣旋數據不可用",
   "Potential tropical cyclone": "潛在熱帶氣旋",
+  "Post-tropical cyclone": "後熱帶氣旋",
   "Hurricane": "颶風",
   "Tropical storm": "熱帶風暴",
   "Tropical depression": "熱帶低壓",
@@ -707,11 +708,15 @@
   "Merge onto {road}": "併入 {road}",
   "maneuver|Merge": "併道",
   "Take the ramp on the {direction} onto {road}": "{direction}駛入匝道，進入 {road}",
+  "Take the ramp {direction} onto {road}": "{direction}駛入匝道，進入 {road}",
   "Take the ramp on the {direction}": "{direction}駛入匝道",
+  "Take the ramp {direction}": "{direction}駛入匝道",
   "Take the ramp onto {road}": "駛入匝道，進入 {road}",
   "Take the ramp": "駛入匝道",
   "Take the exit on the {direction} onto {road}": "從出口{direction}駛出，進入 {road}",
+  "Take the exit {direction} onto {road}": "從出口{direction}駛出，進入 {road}",
   "Take the exit on the {direction}": "從出口{direction}駛出",
+  "Take the exit {direction}": "從出口{direction}駛出",
   "Take the exit onto {road}": "從出口駛出，進入 {road}",
   "Take the exit": "從出口駛出",
   "At the roundabout, take the {exit} exit onto {road}": "在環島從{exit}出口駛出，進入 {road}",
@@ -1599,6 +1604,9 @@
   "LIVE SIGNALS": "實時信號",
   "CCTV layer unavailable": "CCTV 圖層不可用",
   "Link copied!": "鏈接已複製！",
+  "Link shared": "鏈接已分享",
+  "This share link can't be opened": "無法打開此分享鏈接",
+  "Shared vessel is unavailable": "分享的船舶不可用",
   "Copy failed": "複製失敗",
   "Return map to straight-down view": "將地圖恢復為垂直俯視",
   "Tilt map to oblique view": "將地圖傾斜至斜視角",
@@ -1952,6 +1960,8 @@
   "ORBIT": "環繞",
   "Location not found": "未找到位置",
   "Search failed": "搜索失敗",
+  "Check the spelling and press Enter to search again.": "請檢查拼寫，然後按 Enter 重新搜索。",
+  "Press Enter to try again.": "按 Enter 重試。",
   "Detailed outline unavailable": "無法獲取詳細輪廓",
   "Fly to a POI first": "請先飛往一個 POI",
   "Reset to full globe view": "重置為完整地球視圖",
@@ -2977,16 +2987,6 @@
   "Search": "搜索",
   "More": "更多",
   "Panels": "面板",
-  "Post-tropical cyclone": "後熱帶氣旋",
-  "Take the ramp {direction} onto {road}": "{direction}駛入匝道，進入 {road}",
-  "Take the ramp {direction}": "{direction}駛入匝道",
-  "Take the exit {direction} onto {road}": "從出口{direction}駛出，進入 {road}",
-  "Take the exit {direction}": "從出口{direction}駛出",
-  "Link shared": "鏈接已分享",
-  "This share link can't be opened": "無法打開此分享鏈接",
-  "Shared vessel is unavailable": "分享的船舶不可用",
-  "Check the spelling and press Enter to search again.": "請檢查拼寫，然後按 Enter 重新搜索。",
-  "Press Enter to try again.": "按 Enter 重試。",
   "Recent speech": "最近語音",
   "Voice Settings": "語音設置",
   "Preview": "預覽",
@@ -3025,8 +3025,19 @@
     "other": "{count} 個地標"
   },
   "S2 Underground publishes these KMZ products to GitHub. New uploads are detected within seconds and replace the previous edition automatically. Click a marker for its report.": "S2 Underground 在 GitHub 發布這些 KMZ 產品。新上傳的內容會在數秒內被檢測到，並自動替換舊版本。點擊標記查看報告。",
-  "routing busy — too many routes at once": "路線服務繁忙：同時請求的路線過多",
-  "route proxy error": "路線代理出錯",
+  "fire confidence filter|All": "全部",
+  "fire confidence filter|Nominal+": "中+",
+  "fire confidence filter|High": "高",
+  "Every detection — many of the strongest fires are rated low confidence": "所有火點探測——許多強度最高的火點被評為低置信度",
+  "Nominal and high confidence detections": "中、高置信度的火點探測",
+  "High confidence detections only": "僅高置信度的火點探測",
+  "Fire intensity (FRP)": "火勢強度（FRP）",
+  "≥ {value} MW": "≥ {value} MW",
+  "Confidence": "置信度",
+  "Minimum fire radiative power, megawatts": "最小火輻射功率（兆瓦）",
+  "fire intensity filter|All": "全部",
+  "Detection confidence": "探測置信度",
+  "{shown} of {total} shown": "顯示 {shown} / {total}",
   "{lower} to {upper}": "{lower} 至 {upper}",
   "Up to {upper}": "最高 {upper}",
   "From {lower}": "最低 {lower}",
@@ -3039,6 +3050,8 @@
   "Prohibited": "禁區",
   "Restricted": "限制區",
   "Prohibited & Restricted Airspace": "禁區與限制區空域",
+  "routing busy — too many routes at once": "路線服務繁忙：同時請求的路線過多",
+  "route proxy error": "路線代理出錯",
   "AUTHORING": "創作",
   "Create and edit scenes": "創建和編輯場景",
   "SCENE": "場景",
@@ -3064,19 +3077,6 @@
   "Download this scene as JSON or an asset bundle": "將此場景下載為 JSON 或資源包",
   "Left panels": "左側面板",
   "Right panels": "右側面板",
-  "fire confidence filter|All": "全部",
-  "fire confidence filter|Nominal+": "中+",
-  "fire confidence filter|High": "高",
-  "Every detection — many of the strongest fires are rated low confidence": "所有火點探測——許多強度最高的火點被評為低置信度",
-  "Nominal and high confidence detections": "中、高置信度的火點探測",
-  "High confidence detections only": "僅高置信度的火點探測",
-  "Fire intensity (FRP)": "火勢強度（FRP）",
-  "≥ {value} MW": "≥ {value} MW",
-  "Confidence": "置信度",
-  "Minimum fire radiative power, megawatts": "最小火輻射功率（兆瓦）",
-  "fire intensity filter|All": "全部",
-  "Detection confidence": "探測置信度",
-  "{shown} of {total} shown": "顯示 {shown} / {total}",
   "UTILITIES": "工具",
   "Exit cockpit to fly to a drawing": "請先退出座艙，再飛往已繪製的形狀",
   "Directions, drawing and your own files": "路線導航、繪製和你自己的文件",