Run lint and tests as Dockerfile phases built with --no-cache (closes #202)

script/check, cibuild, docker, lint, test, setup and install-precommit
are now the copies from sneak/prompts main, unchanged: lint and test
each build their Dockerfile phase with --no-cache, and cibuild runs
bootstrap and check before building the image. The lint phase runs
golangci-lint from the image REPO_POLICIES.md names, with libvips-dev
from apt-get; the test phase runs the tests with a 90-second timeout;
the build stage depends on both. Dockerfile.lint and CHECK_EPOCH are
gone, the formatting check stays on the host, and make docker-versioned
and docker-test call the scripts. Without VERSION the stage that
compiles still takes the version from git describe, per issue 166.

Model: opus-5-5

Makefile

@@ -32,11 +32,11 @@ fmt-check:
 fmt:
 	@script/fmt
 
-# Run linter
+# Run linter (the lint phase of the Dockerfile)
 lint:
 	@script/lint
 
-# Run tests (30-second timeout)
+# Run tests (the test phase of the Dockerfile)
 test:
 	@script/test
 
@@ -59,20 +59,20 @@ docker:
 docker-smoke:
 	@script/docker-smoke
 
-# Build Docker image tagged pixad:$(VERSION) and pixad:latest
+# Build Docker image as `make docker` does, and also tag it pixa:$(VERSION)
 docker-versioned:
-	docker build --build-arg VERSION=$(VERSION) -t pixad:$(VERSION) -t pixad:latest .
+	@script/docker
+	docker tag pixa pixa:$(VERSION)
 
-# Run tests in Docker (needed for CGO/libvips)
+# Run tests in Docker, as `make test` does
 docker-test:
-	docker build --target builder --build-arg VERSION=$(VERSION) -t pixad-builder .
-	docker run --rm pixad-builder sh -c "CGO_ENABLED=1 GOTOOLCHAIN=auto go test -v ./..."
+	@script/test
 
 # Run local dev server in Docker
 devserver: docker-versioned devserver-stop
 	docker run -d --name pixad-dev -p 8080:8080 \
 		-v $(CURDIR)/config.dev.yml:/etc/pixa/config.yml:ro \
-		pixad:latest
+		pixa:latest
 	@echo "pixad running at http://localhost:8080"
 
 # Stop dev server