Per the owner ruling on issue 40, linting and testing are phases of the
main Dockerfile rather than a separate lint file. script/lint and
script/test each build one phase by name with caching disabled, and the
final stage copies a harmless file from each so the image cannot be built
unless both passed — the ordering trick already in template-app-go's
Dockerfile, extended to the test phase. A phase that is not the last
stage is built only when something depends on it or --target names it, so
the gates are always invoked by name and the edges are kept. Every build
in script/ is tagged. No config verify step; fmt stays on the host. This
closes issue 30 too: a container has its own result cache and lock.
Model: opus-5
