Does use of computer translation as an aide when writing a paper require a citation or disclosure?
My opinion (note: opinion) is that you don't need to do a citation here as the words are yours originally and the meaning/essence isn't intended to be modified in any way. 

However, my opinion, also, is that it might be useful to note that auto translation was done. This is just so that a reader fluent in the translated language might be forewarned that any anomalies of language might be explained by the use of the translator. 

I think that the workflow in such a case is to tweak the translation in any case as such things are still far from perfect. In this case, especially, it is clear that the translator is just a tool. You state, in fact, that this is your workflow, of course.