CARD P2  (written 2026-09-26 02:22:03 -0700, before compile) — INSTRUMENT ONLY, NEVER A LANDING (rule 20/21: fixed conditions)
Question: is the gun cross-jump family (+22 B; def-stand magnitude term order (k*k+i*i)+j*j vs January i,j,k, which
prevents January's def-crouch/def-stand tail merge) value-number-class sensitive (S3-V3/V6: pointer-temp base key =
VN ordinal mod 4)? P1 was not a valid VN instrument (k=1..3 identical objects).
Probe: on HEAD, right after `real_vector3d desired_facing = actor->input.aiming_vector;` in the gun block insert k
known-false tests of the NULL-initialised pointer (C2 folds each after VN; C1 cannot):
  k=1: if (gun_offset) color = global_real_argb_magenta;
  k=2: + if (gun_offset) color = global_real_argb_pink;
  k=3: + if (gun_offset) color = global_real_argb_blue;
Prediction H-VN: the def-crouch/def-stand pointer temps are created after these statements; if their keys depend on VN
ordinal mod 4, at least one k flips the def-stand order and restores the tail merge (-22 B, gun regions vanish).
Null result in all three = record negative for this instrument.
