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),