test: drive useFocusTrap's Shift+Tab wrap and other-key return end to end

[hivecommons-hive]

Test Improvement

Adds two end-to-end cases to tests/e2e/community-people.spec.js — the spec
that already owns the PersonDialog lightbox — driving two arms of
src/components/hooks/useFocusTrap.js that no spec in tests/e2e/ had ever
executed in a browser:

new case	arm it drives
Shift+Tab from the first focusable element wraps to the last	useFocusTrap.js:38-40 — if (event.shiftKey && document.activeElement === first) { event.preventDefault(); last.focus(); }. No e2e spec pressed Shift+Tab at all, so forward tabbing short-circuited on event.shiftKey and the comparison was never evaluated.
a key that is neither Escape nor Tab leaves the dialog alone	useFocusTrap.js:33 — if (event.key !== 'Tab') return;. The handler is bound to document and sees every keystroke on the page, but nothing asserted that an ordinary key leaves the dialog visible and focus unmoved.

tests/e2e/accessibility.spec.js cannot reach either arm: axe-core scans
static markup and never drives the keyboard. A dialog that leaked focus to the
page behind it on Shift+Tab — WCAG 2.1 2.1.2 No Keyboard Trap / 2.4.3
Focus Order — would ship green today.

No production code changes; one test file.

Evidence

• Unit (npm run test:unit:coverage, TZ=UTC node tests/tools/coverage-report.mjs,
  node v26.10.0, local, base 900592b): src/components/hooks/useFocusTrap.js
  100.00% lines / 100.00% regions. This is an e2e-only gap, so the rules put
  it at medium priority rather than high.

• E2E (local npm run build:e2e:coverage, e2e-coverage-run.mjs init,
  npm run test:e2e:coverage with E2E_COVERAGE_DIR/E2E_COVERAGE_RUN_ID,
  seal --status passed, e2e-coverage-report.mjs --input <dir> --build build):

  	useFocusTrap.js regions	src files
  base 900592b, 298 passed	62.96%	466 / 377 / 80.90%
  this branch, 300 passed	64.29%	467 / 379 / 81.16%

  The base figure reproduces CI job End-to-end coverage (workflow
  Validate repository, run
  37164361552) at
  468 / 379 / 80.98% to within one region. npm run test:unit:coverage:check
  and npm run check:format both pass on this branch.

A caveat worth stating plainly

The two arms are now provably executed — Shift+Tab landing focus on the
last focusable element can only happen if last.focus() ran — yet the region
keys 33:31:33:38, 38:24:40:21 and 40:18:43:22 stay at zero in the report,
while a newly emitted key covering the same source (33:6:33:38, count 3)
appears beside them. That is the drifted-span defect already recorded in #1079
and #1066, observed here on a third component; it is why the gate moves by
+2 regions rather than by the five lines involved. It is not a reason to
withhold the tests, and this PR deliberately does not touch
tests/tools/e2e-coverage-report.mjs, which #1040, #1051, #1070 and #1072 are
already rewriting.

Coordination

This PR claims exactly one file, tests/e2e/community-people.spec.js, and one
production surface, src/components/hooks/useFocusTrap.js. Neither is touched
by any open PR: #1058 claims tests/e2e/interactions.spec.js, #1060
tests/e2e/member-directory.spec.js, #1075
tests/e2e/member-directory-freshness.spec.js, #1054
tests/e2e/data-fixtures.spec.js (and src/lib/profile-links.mjs), and #1034 /
#1078 tests/e2e-data-fixtures.test.mjs. Branch cut from a fresh
origin/main at 900592b.

Related Issue

Closes #1080

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[hivecommons-hive]

Important

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