Add Mellat e-payment, videos/instructions CMS, and legacy domain lookup.

Store gateway credentials per business, initiate/verify Mellat at checkout, and resolve old CMS ids from domains in the migrate modal.

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

src/cart/dto/cart.dto.ts

@@ -2,6 +2,7 @@ import {
   IsInt,
   IsOptional,
   IsString,
+  IsUrl,
   MaxLength,
   Min,
   MinLength,
@@ -67,6 +68,14 @@ export class CheckoutCartDto {
   @IsString()
   customerNotes?: string;
 
+  /**
+   * Absolute URL the bank callback redirects the shopper to after payment.
+   * Required when payment.type is e_payment_gate.
+   */
+  @IsOptional()
+  @IsUrl({ require_protocol: true, require_tld: false })
+  returnUrl?: string;
+
   @ValidateNested()
   @Type(() => CreateTransactionPaymentDto)
   payment!: CreateTransactionPaymentDto;