refactor: remove PYMS microservice, use ZarinPal directly in CMS

- Remove PYMSPaymentService.cs and PYMS proto files
- Remove 'pyms' case from DI ConfigureServices
- Remove PYMS config from appsettings
- Switch PaymentProvider to 'zarinpal' (direct integration)
- ZarinPalPaymentService handles sandbox/production, verify, errors
- PYMS deployment/service/ingress removed from K8s

src/CMSMicroservice.WebApi/appsettings.json

@@ -1,8 +1,5 @@
 {
-  "PaymentProvider": "pyms",
-  "PYMS": {
-    "Address": "http://pyms-svc.default.svc.cluster.local:80"
-  },
+  "PaymentProvider": "zarinpal",
   "ZarinPal": {
     "MerchantId": "6b098fc8-f490-47a1-aac3-1de1a1b84404",
     "UseSandbox": true