Fix Tahesab ByCode list body key causing 502 on range search.

Use Dolistmoshtari as documented and surface upstream error text in the UI.

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

apps/api/src/integrations/tahesab/tahesab-methods.ts

@@ -183,9 +183,10 @@ export class TahesabApi {
   }
 
   doListMoshtariByCode(fromCode: number, toCode: number) {
+    // OpenAPI/Postman: کلید body برای ByCode دقیقاً «Dolistmoshtari» است (حساس به حروف)
     return this.call(
       'DoListMoshtari-ByCode',
-      'DoListMoshtari',
+      'Dolistmoshtari',
       [fromCode, toCode],
     );
   }