fix(i18n): add worktree translation to all 19 third-language dicts (#285)

PR #285 added the zh/en 'worktree' key but the 19 third-language dicts
(de/fr/pt/ko/ar/hi/id/tr/vi/th/ru/it/nl/sv/pl/zhHK/zhTW/zhMO) were missing
it — only ja was patched in the prior commit. The dicts are typed
Record<keyof typeof zh, string> via an unchecked 'as' cast, so tsc did
not catch the gap.

This commit:
- adds the worktree translation to all 19 dicts
- strengthens tests/locales.spec.ts to assert key-set equality for EVERY
  shipped dictionary (not just zh/en/ja), preventing future regressions

tests/locales.spec.ts

@@ -6,7 +6,7 @@
  * interpolation.
  */
 import { afterEach, describe, expect, it } from 'vitest'
-import { LOCALE_NS, attachBetterLocale, attachLocale, en, isZh, ja, relativeTime, t, zh } from '../src/client/locales.ts'
+import { LOCALE_NS, attachBetterLocale, attachLocale, en, isZh, ja, relativeTime, t, zh, de, fr, pt, ko, ar, hi, id as idDict, tr, vi, th, ru, it as itDict, nl, sv, pl, zhHK, zhTW, zhMO } from '../src/client/locales.ts'
 
 /** Minimal structural fake of the DSH LocaleService face the sidebar uses. */
 class FakeLocale {
@@ -111,6 +111,18 @@ describe('locales (DSH i18n following)', () => {
   it('keeps the ja dictionary key-set-equal to zh', () => {
     expect(Object.keys(ja).sort()).toEqual(Object.keys(zh).sort())
   })
+
+  it('keeps every shipped third-language dictionary key-set-equal to zh', () => {
+    // The third-language dicts are typed `Record<keyof typeof zh, string>` via
+    // an `as` cast (unchecked by tsc). This test catches missing/extra keys
+    // introduced when a zh key is added without updating every language.
+    const thirdLangs = {
+      de, fr, pt, ko, ar, hi, idDict, tr, vi, th, ru, itDict, nl, sv, pl, zhHK, zhTW, zhMO,
+    }
+    for (const [lang, dict] of Object.entries(thirdLangs)) {
+      expect(Object.keys(dict as Record<string, string>).sort(), lang).toEqual(Object.keys(zh).sort())
+    }
+  })
 })
 
 /** Minimal fake of the better-locale override store (the subset t()/isZh() read). */