A round of sharpening across the app:

• VIP tier editor reworked — tiers are now defined by a unified criteria list with a "Tiers qualify by" switcher. Mix points, spend, orders, and more per tier instead of committing the whole ladder to one basis.
• Denominators in earning rates — rates can now be "N points per Y spent", not just per single currency unit. 5 points per 100 Kč reads the way merchants actually think.
• Email history per customer — the customer page now lists every loyalty email sent to them, with delivery and open status.
• Widget variant tracking — product-page points now follow variant changes on all themes.
• Hardened session-token verification on storefront APIs.