feat(editor): add --gen-camp-pack convenience composite

Convenience composite command: emits a complete outdoor-camp
scene (tent + firepit + bedroll + canopy + woodpile +
haystack) into <outDir>/ as 6 .wom files in one invocation.

Internally builds a synthetic argv array per primitive and
calls each existing handler — so the camp pack always
matches the per-primitive defaults exactly. Users wanting
custom dimensions should call the individual --gen-mesh-*
commands.

Smoke tested:
  • Creates outDir if needed
  • All 6 .wom files validate clean (--validate-wom PASSED)
  • Vertex / triangle counts match per-primitive defaults
    (firepit 240/120, woodpile 324/288, etc.)

The first composite command in the editor — establishes the
pattern for future packs (--gen-village-pack, --gen-dock-pack,
etc.) by showing how synthetic argv arrays let one handler
delegate to many others without spawning subprocesses.

tools/editor/cli_arg_required.cpp

@@ -55,6 +55,7 @@ const char* const kArgRequired[] = {
     "--gen-mesh-workbench", "--gen-mesh-crate-stack",
     "--gen-mesh-watchpost", "--gen-mesh-water-trough",
     "--gen-mesh-training-dummy", "--gen-mesh-hitching-post",
+    "--gen-camp-pack",
     "--gen-mesh-table", "--gen-mesh-lamppost", "--gen-mesh-bed",
     "--gen-mesh-ladder", "--gen-mesh-well", "--gen-mesh-signpost",
     "--gen-mesh-mailbox", "--gen-mesh-tombstone", "--gen-mesh-crate",