Three findings, all from Copilot's suppressed block.
1. The tests never checked that loadBrowser launches the engine it was
asked for. The failure-path stand-in rejects identically for every
engine, so loadBrowser(root, "firefox") could have called
chromium.launch() and still produced a correctly Firefox-labelled
error. The smokes could not catch it either: the Firefox gate runs
after Chromium is already installed, so a mis-dispatched launch would
SUCCEED and report Firefox coverage that never happened.
Added a success-path test with distinct per-engine spies asserting the
requested engine is invoked, that nothing else is, and that its handle
is what comes back. Mutation-verified: hard-coding playwright.chromium
fails it.
2. The launch-failure message told the reader to run
`npx playwright install --with-deps <engine>`, which is wrong now that
the npm scripts run from the repo root rather than clients/web -- I
introduced that when I removed the `cd`. Playwright is pinned in
clients/web, so a bare root-level npx can fetch a different version and
install a browser revision the pinned one still cannot launch. It now
points at `npm run smoke:web:<engine>` first, and scopes the raw
command to clients/web with the reason.
That message named smoke:web:webkit, which did not exist -- only the
chromium and firefox scripts did. Added it, and a test asserting every
supported engine has one, since a remedy nobody can run is worse than
no remedy. Mutation-verified.
3. AGENTS.md said npm run ci "mirrors" the workflow and then, two
sentences later, that it is "a superset, not a mirror". It now leads
with strict superset, which is the topology this PR is documenting.
The README and AGENTS.md remediation wording is corrected the same way as
the runtime message, so a reader gets the same advice wherever they find
it.
Addresses Copilot review 5030668906 on #2133.
Signed-off-by: cliffhall <cliff@futurescale.com>