=== solang-0001: add_external_functions emits_events Vec::contains O(F×E²) → O(F×E) ===
N=100   k=100  : defective=0.102ms  fixed=0.004ms  speedup=24.3x
N=500   k=500  : defective=2.617ms  fixed=0.025ms  speedup=105.0x
N=1000  k=1000 : defective=8.871ms  fixed=0.046ms  speedup=194.4x
N=2000  k=2000 : defective=37.794ms  fixed=0.169ms  speedup=223.1x

