Recover Safari setup tests on the first attempt

[bbishdotdev]

A setup test could stay on Google until the user started another attempt. The early navigation handler waited for a native diagnostic reply before redirecting, and a missed early event had no recovery path. Remove diagnostics from the redirect’s critical path and add a page-driven recovery path for the same test.

• A narrowly scoped script on the tagged Google setup page wakes the background and recovers the redirect. Native validation rejects expired/superseded attempts, the redirect toggle is respected, and the tab is rechecked before navigation. Duplicate early/page events cause one redirect.
• The tagged Brave page can report completion after it finishes loading, alongside the existing navigation-completion listener. A Google page load or accepted redirect never counts as verified.
• Use existing website permissions. Ordinary searches send no new page messages, and the page script does not inspect page content or send URLs/search terms.
• Include the new resource in both Xcode extension targets and update the Mac verification runbook.

Validation: 69 JavaScript tests passed, including modeled event loss, a stalled/throwing diagnostic bridge, startup storage delay, duplicate events, stale tokens, disabled redirects, tab navigation away, and completion timing. iOS Simulator and macOS app/extension builds passed on Xcode 16.4; packaged resources match source, and the simulator app launches.

The exact physical-phone trigger is not yet confirmed. The runbook includes cold and back-to-back Safari tests; simulator launch and modeled event-loss tests do not replace that acceptance check.