const GRIT_OCTAVES: number
Octaves of grit: from CANONICAL_DETAIL_FLOOR down to GRIT_FLOOR.
Arithmetic rather than a constant, so the two floors stay the only dials. Two
corrections are folded in and each has cost a wrong number once. 2.03 rather
than 2, because that is DEFAULT_FBM's lacunarity and a count derived against
the wrong one lands short. And + 1, because fbm3's first octave is at
the base frequency: N octaves reach CANONICAL_DETAIL_FLOOR / 2.03^(N−1),
so the ratio alone counts the gaps between octaves rather than the octaves.
Without it this returned two for a floor of two meters and stopped at 3.9.