refactor(editor): extract --gen-makefile / --gen-project-makefile into cli_makefile.cpp

Moves the two Makefile-generation handlers (--gen-makefile,
--gen-project-makefile) out of main.cpp into a new
cli_makefile.{hpp,cpp} module. Both emit GNU make recipes
that rebuild every derived output (.glb / .obj / .stl / .html
/ .csv / .md) from sources via wowee_editor flags, with proper
dependency tracking so make can skip already-up-to-date
outputs. Designers can `make -j$(nproc)` to rebuild all zones
in parallel after a content edit.

main.cpp shrinks by 167 lines (3,791 to 3,624).

tools/editor/cli_makefile.hpp

@@ -0,0 +1,20 @@
+#pragma once
+
+namespace wowee {
+namespace editor {
+namespace cli {
+
+// Dispatch the Makefile-generation handlers — emit GNU make
+// recipes that rebuild every derived output (.glb / .obj /
+// .stl / .html / .csv / .md) from sources via wowee_editor
+// flags. Designers can `make -j` to rebuild after editing
+// without remembering which CLI flag does what.
+//   --gen-makefile           per-zone Makefile inside the zone dir
+//   --gen-project-makefile   project-wide Makefile delegating per-zone
+//
+// Returns true if matched; outRc holds the exit code.
+bool handleMakefile(int& i, int argc, char** argv, int& outRc);
+
+} // namespace cli
+} // namespace editor
+} // namespace wowee