feat: replace animated backgrounds with Aceternity UI system

- Add 16 animated background components (aurora, sparkles, vortex, shooting-stars,
  beams, beams-collision, gradient-animation, wavy, lines, boxes, meteors, grid,
  dots, spotlight, noise, ripple, gemini-effect)
- Add full admin BackgroundEditor with live preview, type gallery, per-type settings
- Add BackgroundRenderer with lazy loading, localStorage cache, mobile reduction
- Add input sanitization (sanitizeColor, clampNumber) across all components
- Add translations for en, ru, zh, fa locales
- Remove old Aurora (WebGL/OGL) and AnimatedBackground (CSS wave-blob)
- Remove ogl dependency, add simplex-noise

src/components/layout/AppShell/AppShell.tsx

@@ -23,7 +23,7 @@ import TicketNotificationBell from '@/components/TicketNotificationBell';
 
 import { MobileBottomNav } from './MobileBottomNav';
 import { AppHeader } from './AppHeader';
-import { Aurora } from './Aurora';
+import { BackgroundRenderer } from '@/components/backgrounds/BackgroundRenderer';
 
 // Desktop nav icons
 const HomeIcon = ({ className }: { className?: string }) => (
@@ -279,7 +279,7 @@ export function AppShell({ children }: AppShellProps) {
   return (
     <div className="min-h-screen">
       {/* Animated background */}
-      <Aurora />
+      <BackgroundRenderer />
 
       {/* Global components */}
       <WebSocketNotifications />