Add 1p wallet chooser layout test suite + harness (tooling only)

[djscruggs]

Lands the automated test tooling for the first party wallet chooser dialog with no style changes, so the dialog's CSS can be reworked later against code we own — after the components we use are pulled out of vue-web-request-mediator and that dependency is removed.

This supersedes the tooling portion of #177. #177 also changed web/app.less; this branch deliberately does not (web/app.less is byte-identical to main).

What's here

• Dev-only harness route — /test/wallet-chooser?hints=N&qr=1 mounts the presentational dialog with fake state across wallet counts (0/1/5/15) and the cross-device QR section. No CHAPI registration, wallets, popups, or certs. Excluded from production builds (NODE_ENV !== 'production').
• Layout suite (npm run test:e2e) — Playwright geometric invariants on desktop Chromium, WebKit, Firefox + emulated iPhone 15 and Pixel 7. Asserts structure, not pixels: expected hints render, no scrollbar, header pinned while the list scrolls, panel fills the popup, header border bleeds edge-to-edge, expander/QR behave per wallet count. A small custom reporter (test/e2e/totalsReporter.js) prints an explicit Totals: N/M passed line at the end of the run, alongside the default list output, so the total test count is visible without scrolling up and summing the per-outcome counts (currently 215 = 43 states/assertions × 5 browser projects).
• Screenshot gallery (npm run gallery) — every state × theme × engine, collapsed and expanded, with an index.html contact sheet. Output in the git-ignored test/e2e/gallery/.
• README documents both commands; CHANGELOG entry added (7.5.0).

One intentionally-failing test

has no horizontal overflow is an active test that fails today — left red on purpose, not skipped or fixme'd. It fails because the dialog still relies on the overflow-x: hidden band-aid to hide a real overflow (the headers/separators bleed their border with a negative side-margin that overhangs the border-box flex layout). Running npm run test:e2e locally shows it red as a standing reminder of the deferred CSS work. Once the styles are reworked (see Sequencing), it turns green and proves the band-aid can be removed.

Testing

npm run test:e2e locally → Totals: 190/215 passed · 25 failed. The 25 failures are the has no horizontal overflow cases (one per wallet-count state × 5 engines), which fail as described above; everything else is green. npm run gallery green; lint clean; web/app.less unchanged from main.

CI: deferred for now

This PR intentionally does not run the layout suite in CI — the lint workflow is unchanged, and there's no test-e2e job. If we wired it in now, that job would be red on every push/PR because of the intentionally-failing overflow test above. Our deploy (packaging.yml) triggers on v* tags and does not depend on the test workflow, so a red suite wouldn't actually block a release — but a perpetually-failing check is noise we don't want while the CSS fix is outstanding.

How to add it later (once the overflow test passes), as a sibling of the lint job in .github/workflows/main.yml:

  test-e2e:
    runs-on: ubuntu-latest
    timeout-minutes: 20
    strategy:
      matrix:
        node-version: [24.x]
    steps:
    - uses: actions/checkout@v6
    - name: Use Node.js ${{ matrix.node-version }}
      uses: actions/setup-node@v6
      with:
        node-version: ${{ matrix.node-version }}
    - run: npm install
    # the dev server binds the `authn.localhost` domain; map it to loopback
    - run: echo "127.0.0.1 authn.localhost" | sudo tee -a /etc/hosts
    - run: npx playwright install --with-deps chromium webkit firefox
    - run: npm run test:e2e

Verified working: this exact job ran green in CI on an earlier commit of this branch (lint 30s, e2e ~2m18s across all five projects) before the overflow test was made active. Optionally pair it with the github Playwright reporter (reporter: process.env.CI ? [['list'], ['github']] : 'list') to surface failed/skipped tests as inline annotations on the PR.

Sequencing (after this lands)

1. Pull the used vue-web-request-mediator pieces into authn.io and drop the dependency.
2. Rework the dialog CSS against owned code; the has no horizontal overflow test then passes, and CI can be wired in per the snippet above.

[dlongley]

Thanks, I'll apply my suggestions and merge this in.