Bench: Official interleaved A/B result for M2 (2026-10-03 18:46)

11 A/B pairs per benchmark at full size, order alternated, under 1-min load
12-36 (the machine had no quiet window all day). Median CPython/compiled
speedup: nbody 28.5x (13.6-46.5), spectral-norm 17.9x (1.2-34.0),
fannkuch-redux 29.2x (11.1-38.2), wordfreq 1.1x (0.9-1.6); binary-trees not
compiled (M2b). Outputs identical in every pair.

Refs #41

Author: b-re-w