feat(i18n): add Korean (ko-KR) localization

- Add complete Korean locale across all 7 i18n namespaces
- All translation keys match the English baseline 1:1
- Register ko-KR in SUPPORTED_LOCALES and i18n-check validation

Refs siddharthvaddem/openscreen#406

scripts/i18n-check.mjs

@@ -11,7 +11,7 @@ import path from "node:path";
 
 const LOCALES_DIR = path.resolve("src/i18n/locales");
 const BASE_LOCALE = "en";
-const COMPARE_LOCALES = ["zh-CN", "es", "tr"];
+const COMPARE_LOCALES = ["zh-CN", "es", "tr", "ko-KR"];
 
 function getKeys(obj, prefix = "") {
 	const keys = [];