Route root module files, the root Makefile, and top-level make helpers to
a broad Chainsaw tier that retains kubernetes-latest and withholds only
kubernetes-previous. Full-suite paths and graph-selected suites still
win when the same diff needs broader coverage.
Pin the root-only anchor, mixed-path unions, fail-closed behavior, and
the configured withheld suite with tests that run through both Bats and
the dash-based CI runner.
Assisted-By: LLM
Signed-off-by: Myasnikov Daniil <myasnikovdaniil2001@gmail.com>