Try to reduce flake in a vitest browser test (#3353)

Tentative fix for an intermittent Firefox Vitest browser flake seen in
[this
run](https://github.com/oxidecomputer/console/actions/runs/32997554927/job/98270746108)
and
[earlier](https://github.com/oxidecomputer/console/actions/runs/32167049254/job/95809059849),
where Escape occasionally leaves the ActionMenu open.
`userEvent.type(search, '{Escape}')` explicitly focuses the search input
before sending Escape, which may prevent Firefox CI from missing the
key. Could not repro the flake locally even with CPU maxed out, so I
really have no idea if this will work.

Author: david-crespo

AGENTS.md

@@ -33,6 +33,7 @@
 - Treat Vitest browser specs as small e2e tests: query by accessible role, label, or visible text and use retrying browser matchers. Avoid selectors coupled to CSS classes or internal DOM structure; inspect layout or computed styles only when the behavior has no semantic representation.
 - For sweeping styling changes, coordinate with the visual regression harness and follow `test/visual/README.md` for the workflow.
 - Fix root causes of flaky timing rather than adding `sleep()` workarounds in tests.
+- When an intermittent browser or E2E failure does not reproduce under normal repetition, retry under controlled CPU contention before concluding it is CI-only. Keep the load bounded so the browser and test runner can still make progress, enable failure-only traces when available, and use a shell trap to clean up every churn process.
 - Local Playwright runs write a compact plain-text report to `.e2e-logs/` (gitignored, one timestamped `.log` per run, last 10 kept) via the custom reporter at `test/e2e/compact-reporter.ts`. Top line is `status: ... total=N passed=N ...`; each failure is a `── UNEXPECTED|FLAKY file:line title` block followed by the error (ANSI stripped). Latest run: `ls .e2e-logs | tail -1` — Read it directly, no parsing needed.
 
 # Data fetching pattern

app/ui/lib/ActionMenu.browser.spec.tsx

@@ -67,7 +67,8 @@ test('filters items and resets the search when dismissed', async () => {
     .element(screen.getByRole('option', { name: 'New instance' }))
     .not.toBeInTheDocument()
 
-  await userEvent.keyboard('{Escape}')
+  // Target the input because global keyboard input can miss it in Firefox CI.
+  await userEvent.type(search, '{Escape}')
   await expect
     .element(screen.getByRole('dialog', { name: 'Quick actions' }))
     .not.toBeInTheDocument()