Implemented phase 3 for the POC prototype in the Website service.

Services/Website/Sources/Library/Internal/Pages/SignInPage.swift

@@ -145,7 +145,7 @@ extension SignInPage: Page {
                     }
                 }
                 p(.class("notice notice--warn")) {
-                    "Prototype: passkeys are stubbed. Continue signs you in as the saved demo account; an email signs in as that account, or creates it."
+                    "Prototype: passkeys are stubbed. Continue signs you in as the saved demo buyer; an email signs in as that account, or creates it. To sell, use joost@kestrelrow.example."
                 }
                 p(.class("gate__recover")) {
                     a(.href(.Route.recover)) {