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/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"})