Add audio normalization docs and translations

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).

README.md

@@ -71,7 +71,7 @@ YTSage is designed for users who want a **simple yet powerful YouTube downloader
 | 📑 Embed Chapters                | ✂️ Trim Video Sections                  | 🍪 Login with Cookies              |
 | 📜 Download History              | 🔄 Release Channel Selection            | 🌐 Proxy Support                   |
 | 🎚️ Audio Format Conversion       | 🎬 Video Format Settings                | 🆙 Built-in Updater Tab            |
-| 🌍 Generic Mode  || 🌍 Localization in 14 Languages |                                  |
+| 🌍 Generic Mode                   | 🔊 Audio Normalization (EBU R128)       | 🌍 Localization in 14 Languages    |
 </div>
 
 <a id="installation"></a>
@@ -308,6 +308,7 @@ Notes:
 - **Output Filename Format:** Customize the output filename format using variables like `%(title)s`, `%(uploader)s`, and `%(resolution)s`. Available in **Download Settings → Filename Format**.
 - **Force Output Format:** Force video downloads into a specific container format such as `mp4`, `webm`, or `mkv`. Available in **Download Settings → Output Format Settings**.
 - **Audio Format Conversion:** Convert audio-only downloads to preferred formats such as `AAC`, `MP3`, `FLAC`, `WAV`, `Opus`, `M4A`, `Vorbis`, or `Best`. Available in **Download Settings → Audio Format Settings**.
+- **Audio Normalization:** Standardize volume for audio-only downloads using EBU R128.
 
 </details>