F1: RectDiskOverlap counted a whole square when a cell edge sat exactly r from
the disc centre (`h < yhi`, `-h > ylo`). The comparisons are inclusive now, so
the chord bounds the piece. A proximity burst on an integer centre of mass
delivered 127.32 of 100 at BlastRadius 1 and 100.80 at 3.
F2: delete Detonate's distance prefilter and the radius <= 0 guard. The
prefilter measured from the centre of mass with the bounding box's
half-diagonal, which is not a bound on how far a hull's cells reach; it culled
real overlap on an L-shaped hull and on the shipped Longinus corners.
RectDiskOverlap is the single decider. An untouched entity is still skipped
(its covered list is never allocated).
F3: Detonate iterates a snapshot of zone.Entities, as Zone.Update does. A
lethal blast removed the entity from the live collection and the next MoveNext
threw, leaving the shot pending so it detonated again the next tick.
Tests: tangent discs through Fire and Detonate, an L-shaped hull, grazing
blasts at the farthest corner of Longinus and LonginusX (expected values from
a numeric overlap), and a lethal blast that must resolve once.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
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