Add white buffer to org logo

The org logo goes to the edge, which looks fine in light mode but not so good in dark mode. I would suggest shrinking the logo and adding a white background buffer in the image that is uploaded. 

Could we ask the DevSeed graphics team to make this for us please?

<img width="1080" height="1668" alt="Image" src="https://github.com/user-attachments/assets/541a3fce-a8fa-4b56-94a5-aa99e9dca6f3" />