- Add person_id column to attribute_links table for person attributes
- Add person_attribute column to attribute_definitions to distinguish item vs person attributes
- Add visibility flags: SHOW_IN_CUSTOMERS, SHOW_IN_EMPLOYEES, SHOW_IN_SUPPLIERS
- Add person attribute methods to Attribute model (getAttributesByPerson, savePersonAttributeLink, etc.)
- Refactor Persons controller with shared attribute handling (getPersonAttributes, savePersonAttributes)
- Update Customers, Employees, Suppliers controllers with PSR-12 naming and attribute integration
- Create attributes/person.php view for rendering person attributes
- Add person attributes container to customer/employee/supplier forms
Relates to #3161