docs: drop redundant 'built by Wednesday Solutions' line (#398)

The BUILT BY block above already shows the Wednesday logo and links to wednesday.is, so the body sentence is redundant.

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

@@ -29,8 +29,6 @@
 
 </div>
 
-Off Grid is built by [**Wednesday Solutions**](https://wednesday.is/?utm_source=github&utm_medium=offgrid-readme&utm_content=body-link).
-
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