applicationId uz neni povinne

Credentials/RequestCredentialsProvider.cs

@@ -28,12 +28,12 @@ public sealed class RequestCredentialsProvider
 
         var clientId = HeaderOrDefault(headers, CredentialConstants.ClientIdHeader, _settings.ClientId);
         var clientSecret = HeaderOrDefault(headers, CredentialConstants.ClientSecretHeader, _settings.ClientSecret);
+        // ApplicationId is optional: iDoklad's standard client_credentials grant does not require it.
         var applicationId = HeaderOrDefault(headers, CredentialConstants.ApplicationIdHeader, _settings.ApplicationId);
 
         var missing = new List<string>();
         if (string.IsNullOrWhiteSpace(clientId)) missing.Add(CredentialConstants.ClientIdHeader);
         if (string.IsNullOrWhiteSpace(clientSecret)) missing.Add(CredentialConstants.ClientSecretHeader);
-        if (string.IsNullOrWhiteSpace(applicationId)) missing.Add(CredentialConstants.ApplicationIdHeader);
         if (missing.Count > 0)
         {
             throw new MissingCredentialsException(missing);
@@ -43,7 +43,7 @@ public sealed class RequestCredentialsProvider
         {
             ClientId = clientId!,
             ClientSecret = clientSecret!,
-            ApplicationId = applicationId!,
+            ApplicationId = string.IsNullOrWhiteSpace(applicationId) ? null : applicationId,
             Language = ResolveLanguage(headers),
         };
     }