vad: allow cross-origin credentialed requests to documentations-api (document-link, stamp-verification)

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

infrastructure/istio-config/vad/istio-config.yaml

@@ -138,6 +138,15 @@ spec:
                 - sarex.vadroad.ru
               gateways:
                 - default/platform-gateway
+              cors:
+                allowOrigins:
+                  - exact: "*"
+                extraAllowMethods:
+                  - HEAD
+                extraAllowHeaders:
+                  - Range
+                  - Cache-control
+                allowCredentials: true
               routes:
                 - path:
                     prefix: /documentations/api/