Repair stale README links and duplicate NextDraw entry #92

Upstream Lychee run 37196307745 reports 404 for the Arduino CNC Shield link, both ArtXcode journal links and the EmergentDesign store link. The ArtXcode interviews are available at /journal/marcel-schwittlick-and-the-long-run and /journal/lars-wander-and-mixing-paint-with-code. PR #93 updates those two destinations and removes the two unavailable entries; optional NextDraw consolidation has been withdrawn.