docs: fix broken Wednesday logo src in README (#396)

The dark-mode srcset pointed at https://wednesday.is/logos/wednesday-logo.svg, which 404s (only mobile.wednesday.is served that path). Use the local SVG asset for both themes.

Co-authored-by: User <user@Users-MacBook-Pro.local>
Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: 3 people

README.md

@@ -25,7 +25,7 @@
 
 <sub><b>BUILT BY</b></sub>
 
-<a href="https://wednesday.is/?utm_source=github&utm_medium=offgrid-readme&utm_content=logo"><picture><source media="(prefers-color-scheme: dark)" srcset="https://wednesday.is/logos/wednesday-logo.svg" /><img src="src/assets/wednesday-logo.svg" alt="Wednesday Solutions" height="104" /></picture></a>
+<a href="https://wednesday.is/?utm_source=github&utm_medium=offgrid-readme&utm_content=logo"><img src="src/assets/wednesday-logo.svg" alt="Wednesday Solutions" height="104" /></a>
 
 </div>