feat: web UI redesign with PWA support, voice page, and mobile layout
- Redesign dash/history/notifications/trace pages with unified CSS framework
(ui.css): cards, badges, scrollable tables, responsive grid, PWA shell.
- Add /voice page with chat-bubble transcript, listening indicator, and
push-to-talk button for voice interaction.
- Add mavweb.js: client-side JS for live transcript polling, auto-scroll,
push-to-talk, and service-worker registration.
- Update PWA manifest, icon, and service-worker for installable web app.
- Add WebAuthn credential management (register/list/delete) with modal UI.
- Update main.go: /voice route, WebAuthn handlers, new page navigation.
- Update handlers_test.go for new voice and WebAuthn routes.
kami
7a95097cc7