estadisticas: dead outlier-detection rule, never fires (since MARS-193)

computePositionDetail's >2-sigma outlier test on the 4 group-A tooth positions is unreachable by construction: for n=4, max possible population-sigma deviation from the mean is (n-1)/sqrt(n) = 1.5, always below the 2-sigma threshold. isOutlier has been false for every row since MARS-193 -- the 'Atipico' badge has never rendered in prod. Pinned with a KNOWN-DEFECT test, not fixed, because the right behavior for a 4-position report is a SCOPE decision (redesign the test for small-n, or drop the badge/feature), not a typo fix. Needs Elazar's call on which.