Host-based CLR hosting to avoid dropping executables

Use a PowerShell process that already hosts the CLR to load a compatible managed assembly from a byte array with System.Reflection.Assembly.Load(byte[]), then invoke its parameterless entry point in that same process. Supplying the assembly as bytes avoids writing that assembly as an executable file in this procedure; it does not hide PowerShell script content, runtime activity, or execution telemetry, and it is not cross-process injection.