# هيكلة قاعدة البيانات الشاملة
- **products:** (id, name, description, fulfillment_type [in_stock, on_demand], is_active).
- **product_variants:** (id, product_id, pattern_name, color, sku, stock, cost_price, default_supplier_id, lead_time_days).
- **suppliers:** (id, name, phone, current_balance).
- **purchase_orders:** (id, supplier_id, source_order_id [nullable], status [draft, confirmed, received], total_cost).
- **orders:** (id, user_id, status [pending, pending_supplier, ordered_from_supplier, processing, shipping, delivered, returned], payment_method, total_profit).
- **order_items:** (id, order_id, variant_id, quantity, unit_price, cost_price, fulfillment_status).