feat(editor): add --gen-texture-blueprint drafting-paper grid

63rd procedural texture: minor + major grid lines on a base.
Minor lines at every `minorStride` pixels (default 16);
every `majorEvery` minor lines a thicker major line is drawn
(default every 4). Both axes get the same treatment so the
result is a sectioned drafting / engineer's paper look.

Distinct from --gen-texture-mesh-screen (uniform line
weight) — this is the periodic-emphasis variant. Good for:

  • drafting-table surfaces
  • technical-schematic backdrops
  • architect-shop / cartographer-shop walls
  • engineer / scholar ritual tables
  • star-chart room floors

Default 16-stride / every-4-major gives the classic blue
graph-paper aesthetic at 256x256. First procedural texture
that takes 4 numeric layout params plus W/H — exercises the
new parseOpt* helpers across more args than usual.

tools/editor/cli_help.cpp

@@ -159,6 +159,8 @@ void printUsage(const char* argv0) {
     std::printf("                         Mesh-screen: orthogonal H+V wire grid (window screen / chain-link / sci-fi grille)\n");
     std::printf("  --gen-texture-bamboo <out.png> <bgHex> <bambooHex> [stalkW] [nodeY] [nodeBand] [seed] [W H]\n");
     std::printf("                         Bamboo: vertical stalks with sin² shading + horizontal node bands (jungle / asian-themed)\n");
+    std::printf("  --gen-texture-blueprint <out.png> <bgHex> <lineHex> [minorStride] [majorEvery] [minorW] [majorW] [W H]\n");
+    std::printf("                         Blueprint: minor + major grid lines (technical drawing / drafting paper / engineer's table)\n");
     std::printf("  --add-texture-to-zone <zoneDir> <png-path> [renameTo]\n");
     std::printf("                         Copy an existing PNG into <zoneDir> (optionally renaming it on the way in)\n");
     std::printf("  --gen-mesh <wom-base> <cube|plane|sphere|cylinder|torus|cone|ramp> [size]\n");