fix(readme): replace broken external hawk image with improved local SVG logo

- Removed unreliable openclipart.org hotlink (frequently failed to render on GitHub)
- Switched to assets/logo.svg with proper light/dark theme support via CSS prefers-color-scheme
- Simplified illustration for better scalability at small sizes while retaining character
- Added subtle adaptive frame, refined typography balance and spacing
- Removed duplicate heading for cleaner header
- Updated display width for the new logo

This makes the project branding reliably visible in both GitHub light and dark modes.

Author: Patel230

README.md

@@ -1,9 +1,7 @@
 <p align="center">
-  <img src="https://openclipart.org/download/325423/red-shouldered-hawk.svg" alt="hawk" width="480"/>
+  <img src="assets/logo.svg" alt="hawk" width="580"/>
 </p>
 
-<h1 align="center">AI Coding Agent for Your Terminal</h1>
-
 <p align="center">
   AI coding agent for your terminal — built for <strong>developers</strong>, not teams or enterprises (yet).
 </p>