Add compressed GitHub social preview image (274KB)

Resized to 1280x640 for GitHub repository social preview
(original opengraph-image.png is 2.2MB, GitHub requires <1MB)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: TortoiseWolfe