AMS Lite Threaded Spool for A1 Mini

Modified the upstream spool design to actually fit the AMS Lite, as the original was approx. 10mm too wide. Strengthened the male threads to force solid infill. Added filament retention holes. Note that just like the original design, with the threads fully coupled the two spool halves do not touch at the mating faces, there is a small gap, so don't overtighten! The threads don't continue all the way to the face, probably for strength reasons. I tested with PETG, which should make it more suitable for use in a filament dryer/oven. PLA should work fine as well if you don't need to dry your filament (or do it at lower temps). I was able to mount a Bambu refill, although note that the cardboard tube has a larger diameter hole, and you either tighten the threads with it centered or use a spacer tube if you desire.