Self-host templates

There is a page now for self-hosting things other people wrote: Excalidraw, Open WebUI and Cal.com.

Each one is a prompt rather than a button. You copy it, your agent reads the instructions, clones the source and deploys it. There is no form to fill in and no dashboard step, because the agent is already holding everything the deploy needs.

The pages say up front what we provision for each project, which secrets we generate rather than ask you for, and the one or two things only you can supply. A one-click deploy that then demands a Google OAuth client is worse than a page that warned you.