* docs(readme): add deployment FAQ
Add a FAQ section right after the deploy steps, covering the four most
commonly asked deployment questions:
- GitHub flags the account when the fork reuses this project's name, so
Cloudflare cannot list the repository (404)
- redeploy after deleting the Worker still asks for an invite code,
because D1 / KV were not deleted
- JWT_SECRET set as a build variable instead of a runtime secret
- JWT_SECRET stored as a plain text variable, so it is lost on upgrade
* docs(readme): clarify FAQ and deployment instructions
