chore: improve description of findOrCreateCustomerStep (#12840)

packages/core/core-flows/src/cart/steps/find-or-create-customer.ts

@@ -38,9 +38,14 @@ interface StepCompensateInput {
 
 export const findOrCreateCustomerStepId = "find-or-create-customer"
 /**
- * This step either finds a customer matching the specified ID, or finds / create a customer
+ * This step finds or creates a customer based on the provided ID or email. It prioritizes finding the customer by ID, then by email.
- * matching the specified email. If both ID and email are provided, ID takes precedence.
+ * 
- * If the customer is a guest, the email is updated to the provided email.
+ * The step creates a new customer either if:
+ * 
+ * - No customer is found with the provided ID and email;
+ * - Or if it found the customer by ID but their email does not match the email in the input.
+ * 
+ * The step returns the details of the customer found or created, along with their email.
  */
 export const findOrCreateCustomerStep = createStep(
   findOrCreateCustomerStepId,