fix: update Stripe API version to match SDK v20.4.1

Co-Authored-By: Claude <noreply@anthropic.com>

Author: ianmaccallum

src/lib/stripe.ts

@@ -14,7 +14,7 @@ export {
 } from "./tier-constants";
 
 export const stripe = new Stripe(process.env.STRIPE_SECRET_KEY!, {
-  apiVersion: "2026-01-28.clover",
+  apiVersion: "2026-02-25.clover",
   typescript: true,
 });