Create a new address for a customer.

Address Deduplication: Addresses are automatically deduplicated using a content hash. If you create an address with the same data as an existing address, the system will update the existing address's default flags instead of creating a duplicate.

Default Address Behavior:

• Setting is_default_billing: true will unset the flag on any other address
• Setting is_default_shipping: true will unset the flag on any other address
• A single address can be both default billing and default shipping

Address Validation: New addresses are created with validation_status: pending. Address validation can be triggered separately through integrated tax calculation services (e.g., Avalara).

Country Code: Use ISO 3166-1 alpha-2 country codes (e.g., US, CA, GB, DE).