Deploy all three Workers and the self host button

[hammadmajid]

Part of #3

Question

Deploy all three Workers with their custom domains, and put a Deploy to Cloudflare button in the README that gives a self hoster the whole thing.

• Workers Builds for server, web, and landing from one repo; api.prismark.tech, app.prismark.tech, prismark.tech.
• Secrets and bindings documented: what a self hoster must set, and that Polar's absence turns billing off.
• The button, or the closest thing the research found, in the root README with the self host steps.
• The README's package table and commands updated for the new apps.
• Record the deployment topology as an ADR, amending ADR 0007.