Loyalty webhook payloads and Loyalty endpoints corrected

The Loyalty & Referrals webhook events now show payloads that match what Yotpo sends:

• The referring customer is in referred_by_customer (not referred_by).
• Events include website_url, store_name and published_at.
• VIP Tier Status Changed sends vip_stats in snake_case, for example points_earned and amount_spent_cents.
• Customer objects include is_opt_in, loyalty_opt_in_date, referral_link, referral_discount_code, credit balance and VIP tier fields. Points events include related_order_ids.

New: Account Created (swell/account/created). Triggered when a customer receives the reward for the New Member Reward earning rule.

Loyalty endpoint fixes:

• Adjust Loyalty Customer Points: only customer_email and point_adjustment_amount are required. You can identify the customer with customer_id instead of the email. visible_to_customer is a boolean.
• Record Loyalty Customer Action: reward_points is an integer.
• Retrieve Loyalty Customer Details by Email: send exactly one identifier (customer_email, customer_id, pos_account_id or phone_number). The response fields are now described, including the points history and referral code.

Endpoints affected: all Loyalty & Referrals webhook events, Adjust Loyalty Customer Points, Record Loyalty Customer Action, Retrieve Loyalty Customer Details by Email.