Add Korean interface localization and Hangul font support (#857)

* Show Thai file names and text in the interface with an installed Thai font

A drawing whose file name is Thai showed boxes in its file tab and in the
window title: the interface loaded one Latin system font (plus a CJK font for
the Chinese interface), and neither has Thai.

install_fonts now also adds an installed Thai font (Thonburi, Leelawadee UI,
Noto Sans Thai, Loma...) after the Latin one, in any interface language, since
file names and drawing text are Thai whatever the interface is in. No font is
bundled; without one installed nothing changes.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* Add Korean interface localization and Hangul font support

---------

Co-authored-by: Chanthawat Kiriyadee <enwuft@icloud.com>
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
Co-authored-by: Brandon Thomas <echelon@gmail.com>

docs/control-protocol.md

@@ -152,7 +152,10 @@ Select a language with `engine.execute` and the UI command `ui.language`:
 {"id":1,"method":"engine.execute","params":{"command":"ui.language","params":{"lang":"uk"}}}
 ```
 
-Supported values are `auto`, `en`, `uk`, `pt-BR`, `de`, `es`, `cs`, `ru`, `fr`, `zh` and `it` (Chinese needs an installed CJK font; without one the result's `shown` is `en`). `ui.set` also accepts
+Supported values are `auto`, `en`, `uk`, `pt-BR`, `de`, `es`, `cs`, `ru`, `fr`, `zh`, `it` and `ko`.
+Chinese needs an installed CJK font; Korean needs a font covering the Korean interface from the
+optional craft-fonts input or the operating system. Without a suitable font, the saved choice is
+retained and the result's `shown` is `en`. `ui.set` also accepts
 `{"interfaceLanguage":"uk"}`; `ui.inspect` reports the saved choice in its UI state.
 Invalid choices leave the current language unchanged. Menus, command labels and prompt text
 returned by the control channel retain their English source text. See [localization.md](localization.md).

docs/localization-parity.md

@@ -1,6 +1,6 @@
 # Localization parity
 
-> **Last reviewed:** 2026-10-10 · **Last updated:** 2026-10-11 · **Change:** minor (Czech catalog added: reference/literal coverage, Czech plurals and menu headings) · **Target:** Autodesk AutoCAD 2027 for Mac (26.0)
+> **Last reviewed:** 2026-10-10 · **Last updated:** 2026-10-13 · **Change:** minor (complete current Korean catalog; locale/preferences/live-switch support and Hangul font coverage) · **Target:** Autodesk AutoCAD 2027 for Mac (26.0)
 
 How far CADCraft's interface and drawing text are from AutoCAD's languages. Summarised in
 [ROADMAP.md](../ROADMAP.md#languages); work items in [gaps.md](gaps.md#localization).
@@ -62,16 +62,16 @@ plus native review by a human; extending the catalog to the remaining English-on
 | Indonesian | id | 0 (0%) | 0% | Latin: yes | no | none | 3–5 h |
 | Japanese | ja | 0 (0%) | 0% | CJK glyphs render; IME pending; no vertical text | no | none | 4–6 h |
 | German | de | 989 catalog rows (≈ 100% of the catalog; ≈ 80% of all UI strings, estimated: engine diagnostics and uncatalogued text stay English) | dialogs and tooltips yes; command reference searchable in German | Latin: yes (bundled egui fonts cover ä ö ü Ä Ö Ü ß; long strings will need layout checks) | no native review | partial | 1–2 h |
-| Korean | ko | 0 (0%) | 0% | Hangul renders; macOS Korean IME fixes pending (#118, #119) | no | none | 4–6 h |
+| Korean | ko | 1,235 rows (1,229 ordinary, 4 menu, 2 count); full existing catalog union and marked UI coverage | dialogs, tooltips, Options and translated command-reference labels | UI requires catalog-covering installed or optional craft-fonts Hang/Kore face; English fallback without one; IME fixes still pending | original AI-assisted translation; independent native proofreading pending | complete current catalog; English-only interface gaps remain | native review + platform layout/IME validation |
 | Vietnamese | vi | 0 (0%) | 0% | Latin with stacked diacritics: renders per code point, untested | no | none | 3–5 h |
 | Ukrainian | uk | 989 catalog rows (≈ 100% of the catalog; ≈ 80% of all UI strings, estimated: engine diagnostics and uncatalogued text stay English) | dialogs and tooltips yes; command reference searchable in Ukrainian | Cyrillic: yes (bundled egui fonts) | translated by a contributor; no second review | partial | 2–4 h |
 | Czech | cs | 1,202 catalog rows; reference catalog and marked UI literals covered | dialogs and tooltips yes; contextual menu headings; command reference searchable in Czech | Latin: yes (bundled egui proportional and monospace fonts; Czech letters and quotes tested) | AI-assisted by @Losminek; independent review pass; not yet proofread by a native speaker | complete current catalog; English-only interface gaps remain | native review + shared English-only UI work |
 | Italian | it | 1,227 catalog rows; reference catalog and marked UI literals covered | dialogs and tooltips yes; contextual menu headings (Visualizza / Vista, Edita / Modifica); command reference searchable in Italian | Latin: yes (bundled egui fonts; accented letters tested) | AI-assisted by Emanuele Bottelli (Claude), written from the English strings with Italian desktop-CAD vocabulary; no native proofreading pass yet | complete current catalog; English-only interface gaps remain | native review + shared English-only UI work |
 
-Other languages shipped: Ukrainian, Brazilian Portuguese, German, Czech, Russian, French and Italian. Czech and
+Other languages shipped: Ukrainian, Brazilian Portuguese, German, Czech, Russian, French, Italian and Korean. Czech and
 Brazilian Portuguese cover the reference catalog and every marked UI literal; engine diagnostics and uncatalogued text
 remain English. AutoCAD for Mac ships 7
-non-English languages (zh-Hans, es, fr, ja, de, ko, it); of those, CADCraft now ships German,
+non-English languages (zh-Hans, es, fr, ja, de, ko, it); of those, CADCraft now ships German and Korean,
 and additionally Ukrainian, which AutoCAD for Mac doesn't ship.
 
 **Total to put all twelve at `full`:** about 55–95 Opus 5.5 hours (catalog extension 4–6 h,
@@ -82,6 +82,7 @@ each language, which needs humans. Translations parallelise fully once the catal
 
 | Date | Change | Summary |
 |---|---|---|
+| 2026-10-13 | minor | Korean added: full 1,235-row existing catalog union, single count form, locale/persistence/live-switch tests, and validated Hangul UI fonts; native review and platform verification pending |
 | 2026-10-12 | minor | Italian added: 1,227 rows, one/other plurals, two `menu` headings, locale/preference/plural/font tests; AI-assisted, native proofreading pending |
 | 2026-10-12 | minor | Brazilian Portuguese catalog completed by @RicSchonfelder: 238 rows added (1,231 total), now covering the reference catalog and every marked UI literal, gaps 0; bundled-font glyph test for the catalog's accented letters |
 | 2026-10-11 | minor | Czech added: 1,202 rows, one/few/other plurals, locale/preferences/menu/font/render tests; independent review pass; native proofreading pending |

docs/localization.md

@@ -1,7 +1,7 @@
 # Interface languages
 
 Choose **Edit → Interface Language** and select **Auto (system language)**, **English**,
-**Українська**, **Português (Brasil)**, **Deutsch**, **Español**, **Čeština** (Czech), **Русский**, **Français**, **简体中文**, or **Italiano**.
+**Українська**, **Português (Brasil)**, **Deutsch**, **Español**, **Čeština** (Czech), **Русский**, **Français**, **简体中文**, **Italiano**, or **한국어** (Korean).
 The interface updates without restarting, including the native macOS menus.
 The choice is saved with the other interface preferences (`cadcraft.prefs`, beside the theme):
 eframe storage on the desktop, browser local storage on the web. Installations without a saved
@@ -10,7 +10,7 @@ choice use Auto.
 Auto uses the first supported language in the operating system's preferred locales, or the
 browser's `navigator.languages` on the web. BCP 47 and POSIX tags select their primary language:
 `uk-UA` → `uk`, `de_AT.UTF-8` → `de`, `es-MX` → `es`, `pt_BR.UTF-8` → `pt-BR`,
-`cs-CZ` and `cs_CZ.UTF-8` → `cs`, `it-IT` and `it_CH.UTF-8` → `it`. Unsupported languages fall back to English.
+`cs-CZ` and `cs_CZ.UTF-8` → `cs`, `it-IT` and `it_CH.UTF-8` → `it`, `ko-KR` and `ko_KR.UTF-8` → `ko`. Unsupported languages fall back to English.
 Set `CADCRAFT_LOCALE=cs-CZ` to override the desktop's locale for a launch.
 An explicit saved language choice takes precedence over that override.
 
@@ -21,7 +21,7 @@ Automation can select the language through the existing control channel:
 ```
 
 The `ui.set` method also accepts `{"interfaceLanguage":"cs"}`. Supported values are `auto`,
-`en`, `uk`, `pt-BR`, `de`, `es`, `cs`, `ru`, `fr`, `zh`, and `it`; invalid values are rejected without changing the current
+`en`, `uk`, `pt-BR`, `de`, `es`, `cs`, `ru`, `fr`, `zh`, `it`, and `ko`; invalid values are rejected without changing the current
 selection. Resetting palettes keeps the language choice.
 
 ## Translation coverage
@@ -38,6 +38,13 @@ labels: **Zobrazení / Pohled**, **Kreslení / Kreslit**, **Kótování / Kóta*
 The translation is AI-assisted work by @Losminek, reviewed against Czech desktop and CAD UI
 conventions and an independent review pass; it has not yet been proofread by a native speaker.
 
+Korean has **1,235 rows**: 1,229 ordinary labels, four contextual menu headings, and
+two single-form count templates. It covers the union of the existing catalogs, including
+the Ukrainian reference, the current Czech catalog, Options, prompts, dialogs, and tooltips.
+The translations are original, AI-assisted Korean CAD terminology (for example, 도면층,
+치수, 모깎기, 모따기, 간격띄우기 and 객체 스냅). Independent native proofreading and
+platform-specific layout/IME validation remain follow-up work.
+
 Brazilian Portuguese has 1,231 catalog rows and also covers the reference catalog and every marked UI
 literal: commands, menus, tool groups and tooltips, object snaps, drafting prompts, dialogs and
 Preferences; its gaps are now zero. Its plural rule is `one|other` (0 and 1 are `one`), as CLDR defines
@@ -56,6 +63,20 @@ The bundled egui fonts cover Ukrainian (`Ґґ Єє Іі Її`), German (`ÄÖÜ
 (`ÁČĎÉĚÍŇÓŘŠŤÚŮÝŽ áčďéěíňóřšťúůýž`, including typographic quotes `„…“`).
 The translations add no font assets and work on the web without system fonts.
 
+Korean needs a font that covers **every Hangul character in its catalog** and the language
+picker label. The CJK font loaded in every language (Noto Sans CJK, Microsoft YaHei, PingFang)
+usually covers Hangul already, and then nothing more is loaded. Otherwise, only when Korean is
+chosen, desktop builds look for a `Hang`/`Kore` face from the optional `CRAFT_FONTS_DIR` input,
+then installed fonts: Malgun Gothic/Gulim on Windows, Apple SD Gothic Neo/AppleGothic on macOS,
+and Nanum Gothic or Noto CJK on Linux/FreeBSD. Collection faces are checked individually, and
+file reads/face scans are bounded. No system fonts or new font assets are redistributed.
+
+Web builds cannot read installed fonts and embed no Korean face (to stay within hosting size
+limits), so the web interface stays English when Korean is chosen. Without a font covering the
+catalog, the saved `ko` preference is kept but the interface falls back to English; the language
+command reports that a font is needed, and the picker uses the readable label **Korean** wherever
+Hangul can't be shown. This change does not fix platform IME issues or localize engine output.
+
 ## Adding translations
 
 The implementation follows the display-time catalog pattern used by
@@ -70,6 +91,7 @@ The implementation follows the display-time catalog pattern used by
 - `@plural` entries hold the language's forms for integer counts: Ukrainian `one|few|many`,
   German and Spanish `one|other`, Brazilian Portuguese `one|other` (0 and 1 are `one`),
   Czech `one|few|other` (1; 2–4; everything else, including 0, 11, 21 and 22).
+  Korean has one form (`other`) for all integer counts.
   The API takes `u64`, so fractional counts are not accepted.
 - Register a new catalog in `i18n::LANGUAGES`, add its preference variant and code/name,
   and set its integer plural rule and form count on the `Language` row.