feat: add Navidrome song validator, refs #5

song_of_the_day/Auth/PhoneClaimCodeProviderService.cs

@@ -11,10 +11,9 @@ public class PhoneClaimCodeProviderService
         _signalIntegration = signalIntegration;
     }
 
-    private static Random random = new Random();
-
     private static string RandomString(int length)
     {
+        Random random = new Random();
         const string chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
         return new string(Enumerable.Repeat(chars, length)
             .Select(s => s[random.Next(s.Length)]).ToArray());