Add a Korean catalog (crates/ui-egui/src/i18n/ko.tsv, 4,151 rows) covering
every menu string, every tl! literal and the status and error messages, and
register `ko` in i18n::LANGUAGES (plural_none; every ko-* locale resolves).
- tests: korean_reads_as_korean, ko locale tags, ko in KEEPS_MENU_NAMES and
COMPLETE_MESSAGES; is_cjk covers Hangul so the bundled-font glyph check
leaves Hangul to installed fonts, as it does CJK without craft-fonts.
- Hangul is drawn with an installed system font on the desktop; the web
build still needs a Korean UI face in craft-fonts.
- docs: localization-parity (Korean row, 12-language score 54% -> 63%,
60-100 h), ROADMAP, README, development.md, gaps.md G16,
target-app-parity.
Clean-room: written from the meaning of the English strings in ordinary
Korean vocabulary; no other product's Korean localisation was used.
AI-drafted; native-speaker review welcome.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>