Document Audio Normalization (EBU R128) in README and translated READMEs, and add corresponding localization keys and help text in ytsage language files. Updates include README.md, readme-translations (ar,de,es,fr,hi,id,it,ja,pl,pt,ru,tr,zh) and ytsage/languages JSON files to explain the feature and note that normalization requires re-encoding and forcing a specific audio format (e.g. MP3 or M4A).
Add localized README files and update main README to expose them. Creates readme-translations/*.md (Arabic, German, Spanish, French, Hindi, Indonesian, Italian, Japanese, Polish, Portuguese, Russian, Turkish, Chinese) and adds a language list, README Translations table, and a "Contributing Translations" subsection to README.md so contributors can find and update localized docs.