The ci graph's test:integration task runs `vp run -r test:integration`, but
that script only existed in runtime-tests, so `vp run -r` silently skipped
packages/runtime (11 files, 309 tests) and packages/testing (2 files, 7 tests)
— their unit tests never ran in CI.
Give both packages a test:integration script (= vp test) and make their `test`
compose it, mirroring runtime-tests. `vp run -r test:integration` now covers
all three packages. PTY stays its own branch (no double-run).
Verified: `CI=true vp run ci` on a fresh checkout runs runtime (309) + testing
(7) + runtime-tests (756), exit 0.
Reported-by: @reviewer on PR #25
Yunfei He
90dc89272e