feat(editor): add --bake-wom-collision WOM→WOC pipeline

Convert any WOM mesh into a WOC collision file via
WoweeCollisionBuilder::addMesh, with optional --weld <eps>
that merges shared positions into a single canonical index
before baking. The weld pass is what makes per-face-shaded
procedural primitives produce a properly indexed collision
mesh — adjacent faces that previously authored 4 unique
verts per face now share 1 corner across all incident
faces, so raycasts can traverse edges naturally.

Also accepts --steep <deg> to control the walkable/steep
classification threshold (default 50° from horizontal,
matching the terrain pipeline).

Smoke-tested end-to-end:
  • firepit: 240 verts → WOC with 120 tris (20 walkable
    floor, 20 steep stone walls, rest neutral)
  • tent_solid: 18 verts welds to 6, produces 8-tri WOC
  • canopy: 216 → 56 weld, 108 tris, 30° steep cut

Pairs naturally with --info-mesh-stats --weld for
collision-quality QA before baking.

tools/editor/cli_help.cpp

@@ -491,6 +491,8 @@ void printUsage(const char* argv0) {
     std::printf("                         Bake every zone in a project into one ASCII STL for full-project printing\n");
     std::printf("  --bake-project-glb <projectDir> [out.glb]\n");
     std::printf("                         Bake every zone in a project into one glTF 2.0 (one mesh per zone)\n");
+    std::printf("  --bake-wom-collision <wom-base> [out.woc] [--weld <eps>] [--steep <deg>]\n");
+    std::printf("                         Convert a WOM into a WOC collision file (raycast / walkability mesh) with optional vertex weld\n");
     std::printf("  --import-obj <obj-path> [wom-base]\n");
     std::printf("                         Convert a Wavefront OBJ back into WOM (round-trips with --export-obj)\n");
     std::printf("  --export-wob-obj <wob-base> [out.obj]\n");