feat(i18n): add Korean (ko) translation (#1587)

frontend/scripts/check-i18n-parity.mjs

@@ -285,6 +285,24 @@ const ZH_TW_COGNATES = [
   'EC984C,#6CD4BC,A66EB9,D87694',
 ];
 
+// Korean: script difference means almost nothing is identical.
+// Allow loanwords/acronyms, format strings, and proper nouns that stay verbatim.
+const KO_COGNATES = [
+  'OK', 'Bambu', 'N/A',
+  '({{count}}/8)', '(25%, 50%, 75%)',
+  'Custom Headers (JSON)',
+  'Box label (62 × 29 mm)',
+  'Avery L7160 — A4 sheet (38.1 × 63.5 mm × 21)',
+  'Avery 5160 — US Letter sheet (25.4 × 66.7 mm × 30)',
+  'EC984C,#6CD4BC,A66EB9,D87694',
+  '{{weight}}g',                                      // unit suffix format string
+  'MakerWorld: {{designer}}',                         // brand + placeholder
+  'email',                                            // OIDC claim name placeholder
+  '{{printer}}: {{error}}',                           // pure placeholders
+  '{{name}} — {{stage}} ({{percent}}%) — {{elapsed}}', // pure placeholders
+  'Obico ML API URL',                                 // product name (Obico)
+];
+
 // Spanish cognates — words/phrases that are genuinely identical in Spanish.
 const ES_COGNATES = [
   'Error', 'Firmware', 'General', 'Control', 'Total', 'total', 'Material',
@@ -306,6 +324,7 @@ const IDENTICAL_TO_EN_ALLOWED = {
   fr: new Set(FR_COGNATES),
   it: new Set(IT_COGNATES),
   ja: new Set(JA_COGNATES),
+  ko: new Set(KO_COGNATES),
   es: new Set(ES_COGNATES),
   'pt-BR': new Set(PT_BR_COGNATES),
   'zh-CN': new Set(ZH_CN_COGNATES),

frontend/src/i18n/index.ts

@@ -9,6 +9,7 @@ import es from './locales/es';
 import fr from './locales/fr';
 import ja from './locales/ja';
 import it from './locales/it';
+import ko from './locales/ko';
 import ptBR from './locales/pt-BR';
 import zhCN from './locales/zh-CN';
 import zhTW from './locales/zh-TW';
@@ -20,6 +21,7 @@ const resources = {
   fr: { translation: fr },
   ja: { translation: ja },
   it: { translation: it },
+  ko: { translation: ko },
   'pt-BR': { translation: ptBR },
   'zh-CN': { translation: zhCN },
   'zh-TW': { translation: zhTW },
@@ -31,7 +33,7 @@ i18n
   .init({
     resources,
     fallbackLng: 'en',
-    supportedLngs: ['en', 'de', 'es', 'fr', 'ja', 'it', 'pt-BR', 'zh-CN', 'zh-TW'],
+    supportedLngs: ['en', 'de', 'es', 'fr', 'ja', 'it', 'ko', 'pt-BR', 'zh-CN', 'zh-TW'],
 
     detection: {
       // Order of detection methods
@@ -61,6 +63,7 @@ export const availableLanguages = [
   { code: 'fr', name: 'French', nativeName: 'Français' },
   { code: 'ja', name: 'Japanese', nativeName: '日本語' },
   { code: 'it', name: 'Italian', nativeName: 'Italiano' },
+  { code: 'ko', name: 'Korean', nativeName: '한국어' },
   { code: 'pt-BR', name: 'Portuguese (Brazil)', nativeName: 'Português (Brasil)' },
   { code: 'zh-CN', name: 'Chinese (Simplified)', nativeName: '简体中文' },
   { code: 'zh-TW', name: 'Chinese (Traditional)', nativeName: '繁體中文' },