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_arg_required.cpp

@@ -138,6 +138,7 @@ const char* const kArgRequired[] = {
     "--export-stl", "--import-stl",
     "--bake-zone-glb", "--bake-zone-stl", "--bake-zone-obj",
     "--bake-project-obj", "--bake-project-stl", "--bake-project-glb",
+    "--bake-wom-collision",
     "--convert-m2", "--convert-m2-batch",
     "--convert-wmo", "--convert-wmo-batch",
     "--convert-dbc-json", "--convert-dbc-batch", "--convert-json-dbc",