Social preview / OG banner for GitHub sharing

[astra-intelligence]

Hi Whiteboard team! 👋

I noticed the repo doesn't have a social preview image (the banner that shows up when you share the repo link on Twitter, Slack, Discord, etc.).

I made a concept banner that fits the Whiteboard brand — dark chalkboard-style background with white sketch elements:

What this includes:

• 1200×630 PNG optimized for GitHub social preview
• Dark chalkboard aesthetic with white sketch/doodle elements
• Clear "Whiteboard" title with tagline

I'm happy to submit a PR with this banner if it's useful. I've set up a $1 tip option on Gumroad if you'd like to support the contribution:

https://grantshatz.gumroad.com/l/rgbzfz

Cheers!