[BUG] bins with a file extension in windows need `.cmd` explicitly added

[nlf]

as part of the whole "detect if the thing being run is a batchfile" work, we need to also ensure that the thing we run is the batchfile directly rather than allowing the shell to resolve the extension for us. this is necessary because bins are sometimes published with an extension, and if the extension is a known file type windows won't try to execute the .cmd file next to it - it'll open it in the associated program.