feat(editor): add --gen-texture-scales overlapping-circle pattern

33rd procedural texture: fish / dragon / chain mail scales done
as a half-row-staggered grid of circles whose centers sit at the
bottom-center of each cell. Adjacent rows offset by half a cell
width, with circle radius slightly larger than half the cell, so
the circles interlock into the classic overlapping-scale look.

Three colors: background fills the gaps, scale body fills most of
each circle, and a rim color highlights the top arc to give the
raised / armored feel.

Defaults to 24×16 cells; scaled by cellW × cellH for fine control
of scale density. Useful for chain mail, dragonhide, fish skin,
roof shingles, anywhere needing tiled curved scales.

tools/editor/main.cpp

@@ -150,6 +150,7 @@ int main(int argc, char* argv[]) {
         "--gen-texture-mosaic", "--gen-texture-rust", "--gen-texture-circuit",
         "--gen-texture-coral", "--gen-texture-flame", "--gen-texture-tartan",
         "--gen-texture-argyle", "--gen-texture-herringbone",
+        "--gen-texture-scales",
         "--validate-glb", "--info-glb", "--info-glb-tree", "--info-glb-bytes",
         "--validate-jsondbc", "--check-glb-bounds", "--validate-stl",
         "--validate-png", "--validate-blp",