Official community guidelines

Right now there's no clear set of community guidelines on Patina Project. This leads to confusion about what's allowed and what isn't, especially since some folks mix up rules from other platforms with ours.

It would be great to have a dedicated, easy-to-find page that spells out:

• What kind of content is and isn't allowed

• How moderation works

This would help set expectations for everyone and give mods something concrete to point to. Keeps things fair and transparent.