Add customer multi-level referral profit editor and related settings UI.

Expose enable_customer_level_profit in config and let admins edit per-customer level percents from the customers table/mobile sheets.

Co-authored-by: Cursor <cursoragent@cursor.com>

src/model/customer.ts

@@ -41,5 +41,12 @@ export interface Customer {
   gold: number
   moshtari_code?: string | number | null
   pargar_account_id?: string | number | null
+  /** درصد سود چندسطحی از کارمزد زیرمجموعه‌ها — `{ level, present }` */
+  profit_amount_by_lvl?: ProfitByLevel[]
   // print_name: string
 }
+
+export interface ProfitByLevel {
+  level: number
+  present: number
+}