Category master & API integration

Pull the live category tree with GET /api/v1/seller-erp/categories. The response includes a nested tree (primary → secondary → sub levels) and a flat leaves list with path values for product category_path.

To request a new subcategory, POST /api/v1/seller-erp/categories with primary_category_id, secondary_category_id, and name (parent_id optional for deeper nesting). The same seller API keys and AES-256-CBC encryption apply.

New categories stay pending until an admin approves them. Admins receive an email alert on each request. Once approved, the category goes live and appears in GET /categories for product payloads.

You can also use Category Master in the seller portal to browse the tree and submit requests without calling the API.

See docs/SELLER_ERP_API.md and the in-portal Seller ERP Integration Guide for request examples.