Quote:
Colors from the server are simply passed by the client without modification
Except that the server doesn't actually have the ability to send colors. It can only pass along color identifiers.
No MUD says "{R0,G0,B255}This text is blue".
It says something more like "{blue}This text is color 'blue'."
Note here I made up my own formatting, but this is the basics of ANSI coloring. MUSHclient then says "{blue}" means a particular shade of blue by convention.
ANSI 256 has much more strict of a guideline for color interpretation, because it actually follows a 6x6x6 color cube. So you probably shouldn't change only color 46, because colors 40 and 47 are supposed to correspond with adjacency and then they wouldn't.