Per the owner ruling, linting now runs only inside Docker with the
pinned golangci-lint (v2.12.2). A root Dockerfile.lint runs the linter as
a build step; script/lint just builds it. A GATE_RUN build arg forces the
lint layer to execute every run so a cached build cannot report a false
clean. script/bootstrap no longer installs golangci-lint (the goimports
install stays). The main Dockerfile lint stage calls golangci-lint
directly (no docker-in-docker) and still gates the build. config verify is
omitted because it fetches its schema over an unpinned HTTPS call.
Model: opus-4-8