Add the ReleaseKit tool dependency

docs/roadmap/implementation.md

@@ -107,7 +107,7 @@ deferred as specified in the feature roadmap.
 
 ## Stage 1: declare and prepare the released tool dependency
 
-**Status:** pending. **Prerequisite:** repository orientation and this plan.
+**Status:** complete. **Prerequisite:** repository orientation and this plan.
 
 **Files:** `go.mod`, `go.sum`; affected notices only if existing incorporated
 dependencies change; stage evidence in this plan.
@@ -148,6 +148,18 @@ Confirm that the build leaves `go.mod` and `go.sum` unchanged. Run the current
 default suite once with `GOWORK=off GOTOOLCHAIN=local GOPROXY=off
 GONOPROXY=none GOSUMDB=off go test -mod=readonly -count=1 ./...`.
 
+Observed 2026-10-08: the tool selection resolves to ReleaseKit v0.2.0, with
+Goldmark v2.1.6 and `golang.org/x/mod` v0.40.0 in the tooling graph. The prior
+graph selected `x/mod` v0.8.0 through `x/text`; `go mod why` showed no package
+use in CommandKit, and the current graph uses `x/mod` through ReleaseKit only.
+No incorporated runtime dependency changed, so the OSS policy requires no new
+attribution entry or license text. No source was copied and the tool binary is
+not distributed. `go mod tidy -diff` reported no changes; `go mod verify`
+reported all modules verified. The readonly CLI build succeeded, its `version`
+subcommand reported v0.2.0, and `go.mod` and `go.sum` were unchanged by the build.
+The default offline `go test -mod=readonly -count=1 ./...` passed for the root
+and internal Cobra packages; both example packages compiled.
+
 **Completion:** the root module retains its released tool selection through
 ordinary maintenance, the executable builds, affected notices are correct, and
 existing library checks pass. Commit the stage before proceeding.