Configure Intercom data attributes (custom attributes) for contacts and companies via the Data Attributes API

Steps

1. List existing data attributes: GET /data_attributes?model=contact or ?model=company to understand what is already defined before creating duplicates.
2. Create a new attribute: POST /data_attributes with 'name' (the display name), 'model' ('contact' or 'company'), 'data_type' ('string', 'integer', 'float', 'boolean', 'date', or 'list'), and optionally 'description' and 'options' for list types.
3. The response includes an 'id', the computed 'full_name' (used as the key when setting attribute values on contacts), and 'api_writable' flag.
4. Set attribute values on a contact via PUT /contacts/{id} with 'custom_attributes': {'{full_name}': value} — the key must be the full_name returned when creating the attribute.
5. Update an attribute's description or options via PUT /data_attributes/{attribute_id}; you cannot change the data_type after creation.
6. Archive an attribute you no longer need with PATCH /data_attributes/{attribute_id} by setting 'archived': true — this hides it from the UI but preserves historical data.