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).
