I want to use the authoring tool in conjunction with a regular text editor to modify .json files right on disk [like components.json, for example].
Is this a supported workflow. For the moment, my changes seem to get overwritten by the authoring tool, depending on what I do.....
No I'm afraid not. In the authoring tool, all the content is held in a database then written out to json files when you publish.
When the 'import' feature of the authoring tool is available you should be able to do this though you will have to be constantly exporting/importing.
If you are comfortable editing json files, would it not be easier just to use the framework?