Generate a checkout URL on authority.md for purchasing one or more frameworks, Tools, Playbooks, or Bundles. Accepts 1-50 slugs (personas, Tools, and/or Playbooks, mixed carts allowed). To purchase a Bundle, pass all 10 of its persona slugs (get them from get_persona_details on the bundle slug — they will land on the $29.99 step-pricing tier automatically). Returns a URL the user follows to a checkout page hosted by authority.md that processes payment securely via Stripe. Personas use step pricing; Tools have individual prices; Playbooks are a flat $12.99 each. For current prices call get_persona_details per slug or read https://authority.md/products.json. Confirm with the user which items they want and the total cost BEFORE calling this tool.