Preserve SOAP base64 formatting on modern .NET

Replace attributed transient new SoapBase64Binary(bytes).ToString() calls with a private helper using Convert.ToBase64String. Preserve null results, empty arrays, and the Framework's leading LF and LF before each subsequent 76-character chunk. Evaluate arrays once. Remove unused SOAP/remoting imports. Stored wrappers, parsing, partial types, lambdas, conditional-compilation files, namespace-scoped/global imports, and commented wrapper syntax remain for review.