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/ui/backgrounds/aurora-background.tsx

@@ -0,0 +1,37 @@
+import { cn } from '@/lib/utils';
+
+interface Props {
+  settings: Record<string, unknown>;
+}
+
+export default function AuroraBackground({ settings }: Props) {
+  const speed = (settings.speed as number) ?? 60;
+  const showRadialGradient = (settings.showRadialGradient as boolean) ?? true;
+
+  return (
+    <div className="absolute inset-0 overflow-hidden">
+      <div
+        className={cn(
+          `pointer-events-none absolute -inset-[10px] opacity-50 blur-[10px] invert filter will-change-transform after:animate-aurora`,
+          `[background-image:var(--white-gradient),var(--aurora)] [background-position:50%_50%,50%_50%] [background-size:300%,_200%]`,
+          `after:absolute after:inset-0 after:mix-blend-difference after:content-[""] after:[background-attachment:fixed] after:[background-image:var(--white-gradient),var(--aurora)] after:[background-size:200%,_100%]`,
+          `dark:invert-0 dark:[background-image:var(--dark-gradient),var(--aurora)] after:dark:[background-image:var(--dark-gradient),var(--aurora)]`,
+          showRadialGradient &&
+            `[mask-image:radial-gradient(ellipse_at_100%_0%,black_10%,var(--transparent)_70%)]`,
+        )}
+        style={
+          {
+            '--aurora':
+              'repeating-linear-gradient(100deg,var(--blue-500)_10%,var(--indigo-300)_15%,var(--blue-300)_20%,var(--violet-200)_25%,var(--blue-400)_30%)',
+            '--dark-gradient':
+              'repeating-linear-gradient(100deg,var(--black)_0%,var(--black)_7%,transparent_10%,transparent_12%,var(--black)_16%)',
+            '--white-gradient':
+              'repeating-linear-gradient(100deg,var(--white)_0%,var(--white)_7%,transparent_10%,transparent_12%,var(--white)_16%)',
+            '--transparent': 'transparent',
+            animationDuration: `${speed}s`,
+          } as React.CSSProperties
+        }
+      />
+    </div>
+  );
+}