i18n: add Hungarian (hu) UI translation

Add the Hungarian catalog (4,524 rows): every menu string, every `tl!`
literal, the contextual and `@id` rows, the plurals and the status and
error messages, written from the meaning of the English labels in
general Hungarian vector-illustration vocabulary. Conventions are in the
header of `hu.tsv`.

- Register `hu` ("Magyar") in `i18n::LANGUAGES` as a complete language
  with `plural_none` (a count takes the singular); every `hu-*` locale
  resolves to it.
- Tests: Hungarian joins the menu-label, menu-string, `tl!`-literal and
  message coverage checks; `hungarian_reads_as_hungarian` pins the core
  vocabulary, the plural, the `file.close` override and a nested
  message; ő ű Ő Ű are checked in the bundled UI fonts.
- README, ROADMAP, docs/development.md and docs/localization-parity.md
  list Hungarian.

docs/development.md

@@ -177,7 +177,8 @@ international Spanish; every `es-*` locale such as `es-ES`, `es-MX`, `es-AR` or
 complete; `fr-FR`, `fr-BE`, `fr-CA`, `fr-CH` and every other `fr-*` locale resolve to it), Italian (`it`,
 complete; `it-IT`, `it-CH` and every other `it-*` locale resolve to it), Russian (`ru`, complete; every `ru-*`
 locale such as `ru-RU`, `ru-BY` or `ru-KZ` resolves to it), Ukrainian (`uk`, complete; `uk-UA`,
-`uk_UA.UTF-8` and every other `uk-*` locale resolve to it; integer plurals use one/few/many), Czech (`cs`, every menu label) and Brazilian Portuguese
+`uk_UA.UTF-8` and every other `uk-*` locale resolve to it; integer plurals use one/few/many), Hungarian (`hu`, complete;
+`hu-HU` and every other `hu-*` locale resolve to it; a count takes the singular, so plurals have one form), Czech (`cs`, every menu label) and Brazilian Portuguese
 (`pt-br`, every menu label and every `tl!` literal). Untranslated text falls back to English until its rows are added.
 
 - `tl!("…")` translates a literal into the language the UI is drawn in; `i18n::t(s)` is the same for a
@@ -205,10 +206,10 @@ locale such as `ru-RU`, `ru-BY` or `ru-KZ` resolves to it), Ukrainian (`uk`, com
   control channel, MCP and tests read them) and are translated only where the status bar draws them
   (`i18n::msg`). `@msg` catalog rows hold a whole message or a template such as
   `Couldn't open {name}: {e}`; `{_1}`, `{_2}` … stand for the format string's `{}`, and the values in the
-  placeholders are translated in turn (the reason after `: {e}` is often a message too). Spanish, French, Italian, Japanese, Russian and Ukrainian cover every
+  placeholders are translated in turn (the reason after `: {e}` is often a message too). Spanish, French, Hungarian, Italian, Japanese, Russian and Ukrainian cover every
   message literal the test scan finds (`complete_languages_translate_every_message`, languages listed in
   `COMPLETE_MESSAGES`): a new `Err("…")`, `Other(…)`, `#[error(…)]` or `status(…)` message needs an `es.tsv`,
-  a `fr.tsv`, an `it.tsv`, a `ja.tsv`, a `ru.tsv` and a `uk.tsv` row (`VECTORCRAFT_I18N_DUMP_MESSAGES=messages.txt cargo test -p vectorcraft-ui-egui
+  a `fr.tsv`, a `hu.tsv`, an `it.tsv`, a `ja.tsv`, a `ru.tsv` and a `uk.tsv` row (`VECTORCRAFT_I18N_DUMP_MESSAGES=messages.txt cargo test -p vectorcraft-ui-egui
   complete_languages_translate_every_message` lists them all). Other languages show messages in English
   until they add `@msg` rows.
 - Not translated on purpose: names that are user data (layers, swatches, fonts, documents), the tab

docs/localization-parity.md

@@ -1,6 +1,6 @@
 # Localization parity
 
-> **Last reviewed:** 2026-10-10 · **Last updated:** 2026-10-11 · **Change:** minor (Czech render-site localization follow-up; scores and estimates unchanged) · **Target:** Adobe Illustrator 2026 (30.x)
+> **Last reviewed:** 2026-10-10 · **Last updated:** 2026-10-12 · **Change:** minor (Hungarian catalog added; Czech render-site localization follow-up; scores and estimates unchanged) · **Target:** Adobe Illustrator 2026 (30.x)
 
 Per-language status of VectorCraft's interface. How the catalogs work and how to add a language:
 [`development.md` › Localisation](development.md#localisation). Part of
@@ -49,9 +49,10 @@ plus review. Native-speaker review is human work and isn't in the hours.
 | Italian | `it` | 4,011 / 4,020 | full |
 | Russian | `ru` | 4,009 / 4,020 | full |
 | Ukrainian | `uk` | 4,009 / 4,020 (one/few/many plurals) | full |
+| Hungarian | `hu` | 4,524 rows: menus, `tl!` literals and messages complete (tests); one plural form | full |
 | Czech | `cs` | 4,411 catalog entries, including 636 `@msg` rows (measured locally 2026-10-11); menu, literal and message coverage enforced by tests | catalog complete; render-site gaps reduced; native review pending |
 
-Eleven non-English catalogs in all. Illustrator, as its public documentation lists, ships around two dozen
+Twelve non-English catalogs in all. Illustrator, as its public documentation lists, ships around two dozen
 interface languages (including Korean, Polish, Dutch, Turkish, the Nordic languages, Hungarian, and Middle East
 editions with Arabic and Hebrew); it doesn't ship Hindi, Indonesian or Vietnamese.
 
@@ -78,5 +79,6 @@ font for the web build.
 
 | Date | Change | Summary |
 |---|---|---|
+| 2026-10-12 | minor | Hungarian (`hu`) catalog added, complete under the tests |
 | 2026-10-11 | minor | Czech render-site follow-up: file-dialog filters, diagnostics, preset numbering, contributor tooltips/plurals, gradient grammar and contextual printer mark styles; estimates unchanged |
 | 2026-10-10 | major | First per-language table, measured from the catalog row counts against the complete French catalog |