The release workflow installed Go via actions/setup-go, which pins the
action but not the toolchain tarball it downloads at runtime -- the
compiler that produces the published binaries was the last external
input in the release path verified against nothing in the repo, against
REPO_POLICIES.md's hash-pin rule.
New script/install-go, modelled on script/install-goreleaser, downloads
the exact go.dev archive for go.mod's `go` directive and refuses it
unless its sha256 matches a value committed in the script. release.yml
calls it instead of setup-go and sets GOTOOLCHAIN=local so that exact
compiler builds the release. The version is not duplicated: go.mod owns
it and install-go fails when its committed GO_VERSION disagrees, so
bumping Go edits go.mod, the checksum, and the Dockerfile golang digest
together.
Model: opus-4-8
clawbot