All bitwise & and | comparisons were missing parentheses — Zig's ==
and != bind tighter than & and |, so `flags & 0x8 == 0` parsed as
`flags & (0x8 == 0)` = `flags & 0` = always 0.
Affected: si_frustumCullBBox (behind-camera check never ran, occlusion
flag check always passed), si_processLinkedListCollision (early-out
never triggered, node skip broken, AABB hit test only checked X-axis).
Also adds fastRecip (vrcpss+NR) and cvtss2si helpers for frustumCull
perspective divide optimization (2.0x speedup, was 1.6x).
MarcelineVQ
0576a06ef0