Fixes audio on sites that run their player in an iframe, which is most of
them. Previously the boost silently did nothing there.

Fixes a video going permanently mute after setting a volume and switching to
another stream. Players that reuse one <video> element across streams left it
routed nowhere until the page was reloaded.

Fixes the extension on Chromium builds running Manifest V2, where several
browser APIs are callback-only and the popup failed to open.

An embedded widget could previously relabel the tab as its own origin - an
embedded payment frame could make a stream page read as m.stripe.network, and
"Remember this site" would have saved the setting under that domain.

New: a language picker with all 55 languages, an editor for saved sites that
applies changes to open tabs immediately, volume presets that follow the
configured maximum, and a status line explaining why a page cannot be boosted.
The bypass control now names the current state rather than the action.

NEW PERMISSION: webNavigation
Required to enumerate a tab's frames so the volume reaches a player inside an
iframe. It is used for nothing else: no page content is read, and no browsing
history is collected, stored or transmitted. The add-on still makes no network
requests of any kind.