Sounds like a good challenge. First strip it down, find the mainspring and gears that still move, and replace any worn bearings. Then, instead of a straight tick, wire the second hand to a tiny piezo that buzzes a low frequency. Keep the case open so the light can filter through, maybe paint a few stars on the dial. The real magic comes when you hit the reset, listen to that faint hum, and let the whole room settle into the rhythm. Keep an extra gear set ready – if it stutters, I’ll swap it in and get the lullaby back on track.