Contributor skill README names `./make smoke`, which was renamed

## Page or file `.buildmax/README.md`, line 17. ## What is stale The row describing the `smoke` skill says the `/smoke` slash command is "the manual tool smoke test `./make smoke` drives". That command no longer exists — it was renamed to `./make agent-smoke` when the end-to-end suites landed, because the old name collided with the deployment smokes. ``` $ ./make smoke Error: unknown command: smoke ``` `docs/design/end-to-end-testing.md` records the rename, and `cmd/mk/main.go` dispatches `agent-smoke`. Only this one line still uses the old name. ## What would help Update the line to `./make agent-smoke`. Worth carrying over the distinction the new name exists to make: it drives the agent's tools with a real model and needs an API key, so it is not a deterministic test. ## Verify ```bash ./make help all # the Advanced section lists agent-smoke grep -rn "make smoke" . # no hit outside docs/design, which records the rename ``` `./make check docs` covers the Markdown lint. It needs Node; without it, open the pull request and let CI run that half.