chore: add header image to README for enhanced visual appeal

Author: sena-labs

README.md

@@ -1,5 +1,7 @@
 <div align="center">
 
+<img src="https://capsule-render.vercel.app/api?type=waving&color=0:0d1117,50:1a1b2e,100:2d1b69&height=180&section=header&text=OpenRouter%20Pipe&fontColor=a78bfa&fontSize=42&animation=fadeIn&fontAlignY=36&desc=Open%20WebUI%20%E2%86%94%20OpenRouter%20Integration&descAlignY=56&descColor=8b5cf6" width="100%"/>
+
 <a href="https://github.com/sena-labs/Open-Router-Pipe"><img src="https://img.shields.io/badge/version-0.2.0-0d1117?style=for-the-badge&labelColor=7c3aed&color=0d1117" alt="version"></a>&nbsp;
 <a href="https://www.python.org/"><img src="https://img.shields.io/badge/python-≥3.10-0d1117?style=for-the-badge&logo=python&logoColor=white&labelColor=3776AB" alt="python"></a>&nbsp;
 <a href="LICENSE"><img src="https://img.shields.io/badge/license-MIT-0d1117?style=for-the-badge&labelColor=blue" alt="license"></a>&nbsp;