🌸 Make cards in the section navigation all have the same height

[anaulin]

• https://github.com/zinc-collective/convene/issues/1988

A small beautification tweak to make section navigation cards have a uniform height.

I decided that a max-height wasn't necessary, since we constrain the height of the image and the description length is capped at 300 characters.

I also took the opportunity to expand the seeds file with some hero images and room descriptions.

Before

After