lang/ — i18n Rules

en.json is the source of truth. Always update da.json and de.json when adding or changing keys.
/api/langs globs both *.json and *.lang — both formats coexist.
Loader in app_config.py prefers .json, falls back to .lang.
JS: t(key, default) — Python: LANG.get(key, default)
No emojis or symbol prefixes in translation values used as button labels.