i18n: add Swedish (sv) interface translation (#882)

* 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

* i18n: start the Swedish (sv) interface catalog

Header only, not registered yet: the catalog is filled and the language registered in this
branch, translated from the meaning of CADCraft's English strings and reviewed by a native
Swedish speaker.

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

* i18n: add Swedish (sv) interface translation

A complete 1,235-entry Swedish catalog: every key of the Spanish catalog, Run Script... and the
four menu headings (Visa, Rita, Måttsättning, Ändra). Written from the meaning of CADCraft's
English strings; no other product's localisation and no other catalog was used. AI-assisted; the
terminology and the running app were reviewed by a native speaker. Command-line keywords, system
variables and osnap tokens stay English.

- Preference::Swedish (sv); sv-SE, sv-FI and sv_SE.UTF-8 select it; one|other plurals (the
  English rule).
- sv in REPORTED; tests for locales, saved preference and plurals, menu headings, a live switch,
  dialogs and the Swedish letters in the bundled fonts. No gaps are reported for Swedish.
- ATTRIBUTION, README, docs/localization.md, docs/localization-parity.md,
  docs/control-protocol.md, the options doc comment and a contributors/people.toml entry for
  @holmbom.

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

---------

Co-authored-by: Chanthawat Kiriyadee <enwuft@icloud.com>
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
Co-authored-by: huk082 <89136256+huk082@users.noreply.github.com>
Co-authored-by: Brandon Thomas <echelon@gmail.com>

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**, **Italiano**, or **한국어** (Korean).
+**Українська**, **Português (Brasil)**, **Deutsch**, **Español**, **Čeština** (Czech), **Русский**, **Français**, **简体中文**, **Italiano**, **한국어** (Korean), or **Svenska** (Swedish).
 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 +10,8 @@ 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`, `ko-KR` and `ko_KR.UTF-8` → `ko`. 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`,
+`sv-SE`, `sv-FI` and `sv_SE.UTF-8` → `sv`. 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 +22,7 @@ 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`, `it`, and `ko`; invalid values are rejected without changing the current
+`en`, `uk`, `pt-BR`, `de`, `es`, `cs`, `ru`, `fr`, `zh`, `it`, `ko`, and `sv`; invalid values are rejected without changing the current
 selection. Resetting palettes keeps the language choice.
 
 ## Translation coverage