feat: dark design system + full UI redesign + HTTPS for local dev

- Design system: CSS custom properties (surface levels, accent, status colors, scrollbar, focus-visible)
- Landing: hero with gradient title, feature cards with SVG icons
- Auth pages: consistent card layout with design tokens
- Dashboard: sticky top bar, room grid with status dots, empty state
- Create room: toggle switches, form validation with spinners
- Join flow: room info card with status badge, monospace code input
- Room page: top bar with sidebar toggles (chat/lobby/moderation)
- Chat: bubble messages with optimistic UI, empty state
- Moderation: participant list with avatar initials, kick/ban
- Lobby: waiting animation with pulsing rings, approve/reject
- HTTPS: dev:https script, setup.sh auto-configures BETTER_AUTH_URL
- Auth: trustedOrigins now includes both http:// and https://

package.json

@@ -4,6 +4,7 @@
   "description": "Livekit core - Server for VideoHosting",
   "scripts": {
     "dev": "next dev",
+    "dev:https": "next dev --experimental-https",
     "build": "next build",
     "start": "next start",
     "lint": "tsc --noEmit",