feat(batch1): implement jwt wipe and nonce-required internal logic

dotnet/src/ZB.MOM.NatsNet.Server/Auth/JwtProcessor.cs

@@ -31,6 +31,15 @@ public static class JwtProcessor
     /// </summary>
     public const string JwtPrefix = "eyJ";
 
+    /// <summary>
+    /// Wipes a byte slice by filling with <c>'x'</c>.
+    /// Mirrors Go <c>wipeSlice</c>.
+    /// </summary>
+    public static void WipeSlice(Span<byte> buf)
+    {
+        buf.Fill((byte)'x');
+    }
+
     /// <summary>
     /// Validates that the given IP host address is allowed by the user claims source CIDRs.
     /// Returns true if the host is within any of the allowed CIDRs, or if no CIDRs are specified.