Publish plan

When the user asks for a plan as HTML, finish the plan, then upload it to R2 and give them the public URL so they can open it from any device.

Steps

1. Write the plan as one self-contained HTML file: inline CSS and JS, no local images or relative links, <meta charset="utf-8"> and a viewport meta tag so it reads well on a phone. Save it locally first (for example in the project or /tmp).

2. Run the script next to this file:

   scripts/publish.sh path/to/plan.html [slug]