feat(i18n): offer every ISO 639-1 language

The table was thirty languages typed by hand. It is now generated:
utils/generate_languages.py takes the 184 alpha-2 codes from pycountry,
the display names from CLDR through babel, and the writing direction from
CLDR character order. 159 languages carry their endonym; the remaining 25
have no CLDR entry and carry their English ISO name.

That corrects the right-to-left set, which had four entries and needs ten
— dv, ks, ps, sd, ug and yi were simply missed.

Only 29 languages ship an interface catalogue, so the other 155 render in
English until one is filled. make i18n-ui fills app/i18n/ui/ for them, and
make i18n now covers the interface strings as well; neither asks for a
string a shipped catalogue already answers, so hand-written entries stay.

184 entries do not fit on a screen, so the language menu scrolls inside
itself. overscroll-behavior keeps the page behind it from moving once the
list reaches its end.

babel and pycountry are dev dependencies: the generator needs them, the
application does not.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

app/cypress/e2e/i18n.spec.js

@@ -53,7 +53,7 @@ describe('Language switcher', () => {
     cy.visit('/en/');
   });
 
-  it('names the active language and offers all thirty', () => {
+  it('names the active language and offers every ISO 639-1 code', () => {
     cy.get('#navbarDropdownLanguage')
       .should('have.attr', 'data-bs-toggle', 'dropdown')
       .and('contain.text', 'English');
@@ -61,7 +61,7 @@ describe('Language switcher', () => {
     cy.get('#navbarDropdownLanguage')
       .parent('.nav-item')
       .find('> .dropdown-menu a.dropdown-item')
-      .should('have.length', 30);
+      .should('have.length', 184);
   });
 
   it('marks the active language', () => {
@@ -200,6 +200,21 @@ describe('Translated interface details', () => {
     );
   });
 
+  it('scrolls inside the language menu instead of past the page', () => {
+    cy.viewport(1280, 720);
+    cy.visit('/en/');
+    cy.get('#navbarDropdownLanguage').click();
+
+    cy.get('.dropdown-menu.language-menu').should($menu => {
+      const menu = $menu[0];
+      expect(menu.scrollHeight, 'taller than it shows').to.be.greaterThan(
+        menu.clientHeight,
+      );
+      expect(menu.getBoundingClientRect().height).to.be.lessThan(720);
+      expect(getComputedStyle(menu).overflowY).to.eq('auto');
+    });
+  });
+
   it('offers the switcher in the header only', () => {
     cy.viewport(1280, 720);
     cy.visit('/en/');
@@ -215,7 +230,7 @@ describe('Search engine metadata', () => {
   });
 
   it('declares an alternate for every language plus a default', () => {
-    cy.get('link[rel="alternate"][hreflang]').should('have.length', 31);
+    cy.get('link[rel="alternate"][hreflang]').should('have.length', 185);
     cy.get('link[rel="alternate"][hreflang="x-default"]').should('exist');
     cy.get('link[rel="alternate"][hreflang="ja"]')
       .should('have.attr', 'href')

app/static/css/default.css

@@ -120,6 +120,12 @@ div#navbarNavfooter .navbar-nav {
   flex-wrap: nowrap;
 }
 
+.dropdown-menu.language-menu {
+  max-height: 60vh;
+  overflow-y: auto;
+  overscroll-behavior: contain;
+}
+
 main, footer, header, nav {
   position: relative;
   box-shadow: 

app/templates/moduls/navigation.html.j2

@@ -103,7 +103,7 @@
                 <a class="nav-link dropdown-toggle btn btn-light" id="navbarDropdownLanguage" role="button" data-bs-toggle="dropdown" data-bs-display="dynamic" aria-expanded="false" title="{{ t('Language') }}">
                     <i class="fa-solid fa-language"></i> {{ languages[lang] }}
                 </a>
-                <ul class="dropdown-menu">
+                <ul class="dropdown-menu language-menu">
                     {% for code, endonym in languages.items() %}
                     <li>
                         <a class="dropdown-item {% if code == lang %}active{% endif %}"

app/utils/i18n.py

@@ -11,46 +11,17 @@ from pathlib import Path
 
 import yaml
 
+try:
+    from app.utils.languages import LANGUAGES, RTL_LANGUAGES
+except ImportError:  # pragma: no cover - supports running from the app/ directory.
+    from utils.languages import LANGUAGES, RTL_LANGUAGES
+
 I18N_DIR = Path(__file__).resolve().parent.parent / "i18n"
 UI_DIR = I18N_DIR / "ui"
 CONTENT_DIR = I18N_DIR / "content"
 
 SOURCE_LANGUAGE = "en"
 
-LANGUAGES = {
-    "en": "English",
-    "zh": "中文",
-    "hi": "हिन्दी",
-    "es": "Español",
-    "fr": "Français",
-    "ar": "العربية",
-    "bn": "বাংলা",
-    "pt": "Português",
-    "ru": "Русский",
-    "ur": "اردو",
-    "id": "Bahasa Indonesia",
-    "de": "Deutsch",
-    "ja": "日本語",
-    "tr": "Türkçe",
-    "ko": "한국어",
-    "vi": "Tiếng Việt",
-    "it": "Italiano",
-    "th": "ไทย",
-    "pl": "Polski",
-    "nl": "Nederlands",
-    "uk": "Українська",
-    "fa": "فارسی",
-    "ro": "Română",
-    "el": "Ελληνικά",
-    "cs": "Čeština",
-    "sv": "Svenska",
-    "hu": "Magyar",
-    "he": "עברית",
-    "da": "Dansk",
-    "fi": "Suomi",
-}
-
-RTL_LANGUAGES = frozenset({"ar", "fa", "he", "ur"})
 
 AUTOFILL_KEYS = frozenset({"description", "text", "warning", "info", "subtitel"})
 

app/utils/languages.py

@@ -0,0 +1,196 @@
+"""ISO 639-1 languages, their display names and writing direction.
+
+Generated by utils/generate_languages.py — edit that script, not this file.
+
+Display names are CLDR endonyms where CLDR covers the language and the English
+ISO 639-1 name for the 25 codes it does not.
+"""
+
+LANGUAGES = {
+    "en": "English",
+    "aa": "Qafar",
+    "ab": "Аԥсшәа",
+    "ae": "Avestan",
+    "af": "Afrikaans",
+    "ak": "Akan",
+    "am": "አማርኛ",
+    "an": "aragonés",
+    "ar": "العربية",
+    "as": "অসমীয়া",
+    "av": "Avaric",
+    "ay": "Aymara",
+    "az": "azərbaycan",
+    "ba": "башҡорт теле",
+    "be": "беларуская",
+    "bg": "български",
+    "bi": "Bislama",
+    "bm": "bamanakan",
+    "bn": "বাংলা",
+    "bo": "བོད་སྐད་",
+    "br": "brezhoneg",
+    "bs": "bosanski",
+    "ca": "català",
+    "ce": "нохчийн",
+    "ch": "Chamorro",
+    "co": "corsu",
+    "cr": "Cree",
+    "cs": "čeština",
+    "cu": "церковнослове́нскїй",
+    "cv": "чӑваш",
+    "cy": "Cymraeg",
+    "da": "dansk",
+    "de": "Deutsch",
+    "dv": "ދިވެހިބަސް",
+    "dz": "རྫོང་ཁ",
+    "ee": "eʋegbe",
+    "el": "Ελληνικά",
+    "eo": "Esperanto",
+    "es": "español",
+    "et": "eesti",
+    "eu": "euskara",
+    "fa": "فارسی",
+    "ff": "Pulaar",
+    "fi": "suomi",
+    "fj": "Fijian",
+    "fo": "føroyskt",
+    "fr": "français",
+    "fy": "Frysk",
+    "ga": "Gaeilge",
+    "gd": "Gàidhlig",
+    "gl": "galego",
+    "gn": "avañe’ẽ",
+    "gu": "ગુજરાતી",
+    "gv": "Gaelg",
+    "ha": "Hausa",
+    "he": "עברית",
+    "hi": "हिन्दी",
+    "ho": "Hiri Motu",
+    "hr": "hrvatski",
+    "ht": "Kreyòl Ayisyen",
+    "hu": "magyar",
+    "hy": "հայերեն",
+    "hz": "Herero",
+    "ia": "interlingua",
+    "id": "Indonesia",
+    "ie": "Interlingue",
+    "ig": "Igbo",
+    "ii": "ꆈꌠꉙ",
+    "ik": "Inupiaq",
+    "io": "Ido",
+    "is": "íslenska",
+    "it": "italiano",
+    "iu": "ᐃᓄᒃᑎᑐᑦ",
+    "ja": "日本語",
+    "jv": "Jawa",
+    "ka": "ქართული",
+    "kg": "Kongo",
+    "ki": "Gikuyu",
+    "kj": "Kuanyama",
+    "kk": "қазақ тілі",
+    "kl": "kalaallisut",
+    "km": "ខ្មែរ",
+    "kn": "ಕನ್ನಡ",
+    "ko": "한국어",
+    "kr": "Kanuri",
+    "ks": "کٲشُر",
+    "ku": "kurdî (kurmancî)",
+    "kv": "Komi",
+    "kw": "kernewek",
+    "ky": "кыргызча",
+    "la": "Latina",
+    "lb": "Lëtzebuergesch",
+    "lg": "Luganda",
+    "li": "Limburgan",
+    "ln": "lingála",
+    "lo": "ລາວ",
+    "lt": "lietuvių",
+    "lu": "Tshiluba",
+    "lv": "latviešu",
+    "mg": "Malagasy",
+    "mh": "Marshallese",
+    "mi": "Māori",
+    "mk": "македонски",
+    "ml": "മലയാളം",
+    "mn": "монгол",
+    "mr": "मराठी",
+    "ms": "Melayu",
+    "mt": "Malti",
+    "my": "မြန်မာ",
+    "na": "Nauru",
+    "nb": "norsk bokmål",
+    "nd": "isiNdebele",
+    "ne": "नेपाली",
+    "ng": "Ndonga",
+    "nl": "Nederlands",
+    "nn": "norsk nynorsk",
+    "no": "norsk",
+    "nr": "isiNdebele",
+    "nv": "Diné Bizaad",
+    "ny": "Nyanja",
+    "oc": "occitan",
+    "oj": "Ojibwa",
+    "om": "Oromoo",
+    "or": "ଓଡ଼ିଆ",
+    "os": "ирон",
+    "pa": "ਪੰਜਾਬੀ",
+    "pi": "Pali",
+    "pl": "polski",
+    "ps": "پښتو",
+    "pt": "português",
+    "qu": "Runasimi",
+    "rm": "rumantsch",
+    "rn": "Ikirundi",
+    "ro": "română",
+    "ru": "русский",
+    "rw": "Ikinyarwanda",
+    "sa": "संस्कृत भाषा",
+    "sc": "sardu",
+    "sd": "سنڌي",
+    "se": "davvisámegiella",
+    "sg": "Sängö",
+    "sh": "Serbo-Croatian",
+    "si": "සිංහල",
+    "sk": "slovenčina",
+    "sl": "slovenščina",
+    "sm": "Samoan",
+    "sn": "chiShona",
+    "so": "Soomaali",
+    "sq": "shqip",
+    "sr": "српски",
+    "ss": "siSwati",
+    "st": "Sesotho",
+    "su": "Basa Sunda",
+    "sv": "svenska",
+    "sw": "Kiswahili",
+    "ta": "தமிழ்",
+    "te": "తెలుగు",
+    "tg": "тоҷикӣ",
+    "th": "ไทย",
+    "ti": "ትግርኛ",
+    "tk": "türkmen dili",
+    "tl": "Tagalog",
+    "tn": "Setswana",
+    "to": "lea fakatonga",
+    "tr": "Türkçe",
+    "ts": "Xitsonga",
+    "tt": "татар",
+    "tw": "Twi",
+    "ty": "Tahitian",
+    "ug": "ئۇيغۇرچە",
+    "uk": "українська",
+    "ur": "اردو",
+    "uz": "o‘zbek",
+    "ve": "Tshivenḓa",
+    "vi": "Tiếng Việt",
+    "vo": "Volapük",
+    "wa": "walon",
+    "wo": "Wolof",
+    "xh": "IsiXhosa",
+    "yi": "ייִדיש",
+    "yo": "Èdè Yorùbá",
+    "za": "Vahcuengh",
+    "zh": "中文",
+    "zu": "isiZulu",
+}
+
+RTL_LANGUAGES = frozenset({"ar", "dv", "fa", "he", "ks", "ps", "sd", "ug", "ur", "yi"})