Bucket A: drop tests referencing archived artofwar-decoy-sacrifice

tests: module-level importorskip on all 80 engine-dependent test files

#6 artofwar-lure-the-tiger: adopt rigorously-verified no-cheat redesign

#5 artofwar-indirect-approach: no-cheat redesign — hazard-detour enforced

#4 artofwar-decoy-sacrifice: no-cheat redesign — decoy-sacrifice enforced

Art-of-War long-horizon family: sacrifice/detour, delayed credit