generate_grid.m: pin Rowan's reference config as first entry

[sgrimbly]

src/MATLAB/utils/generate_grid.m line 10 — ensure the canonical reference config (Rowan's original, used for the bulk of the experimental work) is always the first config emitted by generate_grid.

Currently:

% Grid Size: 10, Horizon: 5, Hill: 55, Start Position: 51,
% Food(71,43,57,78), Water(73,33,48,67), Sleep(64,44,49,59)

Fix: hard-code this config at index 1 before the loop emits the parametric variations.