Add sales and milestones

This form writes cited rows into Postgres. It is a skeleton admin path, not an account system. Leave Example checked until the number comes from a public report.

Sent as a bearer token and kept in this browser tab session only. Set ADMIN_TOKEN on the server. You can also add the bundled example rows with the seed script.

The seed script removes the old example rows and upserts cited figures and milestones. It does not invent unit sales.