ok   the round is the banked 64 KiB EPYC ladder
ok   every cell is 8 legs (4 arms x 2 reps)
ok   stealsub keeps the 179 legs the retrospective's 4.1 table names
ok   unfiltered: every rowgate row is reproduced here (20 rows)
ok   unfiltered: floor to rowgate's own 0.1% and verdict exact
ok   unfiltered: reached a non-trivial number of rows
ok   steal < 8.00: every rowgate row is reproduced here (20 rows)
ok   steal < 8.00: floor to rowgate's own 0.1% and verdict exact
ok   steal < 8.00: reached a non-trivial number of rows
ok   t8 m=224 drops ONE leg, so its whole null is EIGHT members
ok   every member of an 8-choose-7 family still reduces
ok   t8 m=128 drops TWO, so C(8,2) = 28
ok   the full-8 reduction is not a member of a d>0 family
ok   call() is strict - an effect EQUAL to the floor is unresolved
ok   call() is symmetric about 1.0
ok   a drop that empties an arm group is not a verdict
ok   pct_le puts a maximum at 100 and a unique minimum at its share
ok   of the C(8,4) = 70 four-leg keeps, exactly 68 are a verdict
ok   SEVEN rungs flip at steal < 8.00%, not the three the handoff names
ok   the flipping rungs are EXACTLY the straddled ones
ok   the three the handoff names are among them
ok   no flip is reproduced by chance less than 20% of the time
ok   at steal < 5.00% t8 m=160 keeps one leg
ok   a rung cut to one leg has NO verdict and NO null
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floornull selftest green on darwin: the reduction reproduces rowgate.py's own table at both settings.