test/package/runtime/ was a manual README-driven corpus with no
target. Its unique surface — the driver's single-file ww test leg,
the unmet-expected-abort outcome, and the published -c binary's own
CLI (repeated globs, -list, -timeout-ms, direct-binary timeout and
descendant handling) — is now asserted by three new @test fns in
package_test.ww; the README drops its manual-run instructions.
Single-directory package-test planner: discovers *.ww, groups white-box
and external <pkg>_test sources, composes the combined test package,
builds it through the sibling ww driver, and runs it with the runtime's
-package/-list/-timeout-ms contract. test/package holds its E2E corpus
and the manual runtime fixture set.
