Replace image in README with updated version

Updated image in README.md to a new source.

Author: pnnbao97

README.md

@@ -7,7 +7,7 @@
 [![Hugging Face 0.5B](https://img.shields.io/badge/%F0%9F%A4%97%20Hugging%20Face-0.5B-yellow)](https://huggingface.co/pnnbao-ump/VieNeu-TTS)
 [![Hugging Face 0.3B](https://img.shields.io/badge/%F0%9F%A4%97%20Hugging%20Face-0.3B-orange)](https://huggingface.co/pnnbao-ump/VieNeu-TTS-0.3B)
 
-<img width="899" height="615" alt="VieNeu-TTS UI" src="https://github.com/user-attachments/assets/7eb9b816-6ab7-4049-866f-f85e36cb9c6f" />
+<img width="1087" height="710" alt="image" src="https://github.com/user-attachments/assets/5534b5db-f30b-4d27-8a35-80f1cf6e5d4d" />
 
 **VieNeu-TTS** is an advanced on-device Vietnamese Text-to-Speech (TTS) model with **instant voice cloning**.