Slot family

A slot is a pill-shaped 2D primitive: two parallel sides connected by two semicircular ends. Three constructors target the same geometry:

SlotCenterToCenter(p1, p2, height)             # endpoints of the centerline
SlotOverall(center, width, height)             # bounding-rectangle dimensions
SlotCenterPoint(center, point, height)         # center + endpoint pair

All expand to a CustomClosedShape (2 lines + 2 arcs) and compose with Extrusion for cuts or pads.