There is nothing to do at CAM level to support the BitRunner, it will pick up the M3/M5 commands that already exist in the generated G-code, to start/stop the router.
To support the BitSetter workflow, you can use @neilferreri’s post-processor for VCarve, and when you save multiple toolpaths using multiple tools in the same output file in VCarve, it will insert the appropriate tool change commands for you.