Fix PyPI badge link and add platform badge

Update README badges: change the PyPI badge URL to the official PyPI project page (pypi.org) and add a 'Supported Platforms' badge indicating cross-platform support (linked to releases). This improves badge accuracy and highlights platform compatibility in the project README.

README.md

@@ -3,12 +3,13 @@
 <img src="branding\svg\ytsage-wordmark.svg" width="400" alt="ytsage-wordmark">
 <img src="branding\screenshots\main.png" width="800" alt="YTSage Interface"/>
 
-[![PyPI version](https://img.shields.io/pypi/v/ytsage?color=dc2626&style=for-the-badge&logo=pypi&logoColor=white)](https://badge.fury.io/py/ytsage)
+[![PyPI version](https://img.shields.io/pypi/v/ytsage?color=dc2626&style=for-the-badge&logo=pypi&logoColor=white)](https://pypi.org/project/ytsage/)
 [![License: MIT](https://img.shields.io/badge/License-MIT-374151?style=for-the-badge&logo=opensource&logoColor=white)](https://opensource.org/licenses/MIT)
 [![Python 3.10+](https://img.shields.io/badge/python-3.10+-1f2937?style=for-the-badge&logo=python&logoColor=white)](https://www.python.org/downloads/)
 [![PyPI Downloads](https://img.shields.io/pepy/dt/ytsage?color=4b5563&style=for-the-badge&label=downloads&logo=python&logoColor=white)](https://pepy.tech/project/ytsage)
 [![GitHub Downloads](https://img.shields.io/github/downloads/oop7/YTSage/total?color=4b5563&style=for-the-badge&label=downloads&logo=github&logoColor=white)](https://github.com/oop7/YTSage/releases)
 [![GitHub Stars](https://img.shields.io/github/stars/oop7/YTSage?color=dc2626&style=for-the-badge&logo=github&logoColor=white)](https://github.com/oop7/YTSage/stargazers)
+[![Supported Platforms](https://img.shields.io/badge/platform-cross--platform-4b5563?style=for-the-badge&logo=github&logoColor=white)](https://github.com/oop7/YTSage/releases)
 
 **A modern YouTube downloader with a clean PySide6 interface.**  
 Download videos in any quality, extract audio, fetch subtitles, and more.