Project architecture lists belong in makefile.builder, not .env.builder.
deb/push-deb fan out when ARCH is omitted; Docker platforms derive from
ARCHES. Legacy makefiles without ARCHES keep the old single-arch behavior.
Give ack, builder, and deployer an explicit init/check mode that reports
missing project config instead of failing mid-work. Point builder at
makefile.builder so its contract targets do not collide with an existing
Makefile.
laily