Removes the [tool.mypy] config block and the dev-group entry, then regenerates uv.lock with the uv lock resolver; the lockfile drops mypy, mypy-extensions, pathspec, and librt while retaining typing-extensions. Removes all five Makefile sites: the MYPY variable, the format: conditional, the clean: cache entry, the install-checks: stage, and the versions: grep token. Updates the stale docs lines. mypy was configured with ignore_errors = true and invoked with || true, so it gated nothing. No replacement type checker; type annotations are unchanged.