feat: Add CHORUS teaser website with mobile-responsive design

- Created complete Next.js 15 teaser website with CHORUS brand styling
- Implemented mobile-responsive 3D logo (128px mobile, 512px desktop)
- Added proper Exo font loading via Next.js Google Fonts for iOS/Chrome compatibility
- Built comprehensive early access form with GDPR compliance and rate limiting
- Integrated PostgreSQL database with complete schema for lead capture
- Added scroll indicators that auto-hide when scrolling begins
- Optimized mobile modal forms with proper scrolling and submit button access
- Deployed via Docker Swarm with Traefik SSL termination at chorus.services
- Includes database migrations, consent tracking, and email notifications

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

modules/teaser/hooks/useIntersectionObserver.ts

@@ -0,0 +1,49 @@
+'use client';
+
+import { useEffect, useRef, useState } from 'react';
+
+interface IntersectionObserverOptions {
+  threshold?: number;
+  rootMargin?: string;
+  triggerOnce?: boolean;
+}
+
+export function useIntersectionObserver(
+  options: IntersectionObserverOptions = {}
+) {
+  const { threshold = 0.1, rootMargin = '0px 0px -100px 0px', triggerOnce = true } = options;
+  const [isIntersecting, setIsIntersecting] = useState(false);
+  const [hasIntersected, setHasIntersected] = useState(false);
+  const elementRef = useRef<HTMLDivElement>(null);
+
+  useEffect(() => {
+    const element = elementRef.current;
+    if (!element) return;
+
+    const observer = new IntersectionObserver(
+      ([entry]) => {
+        const isVisible = entry.isIntersecting;
+        setIsIntersecting(isVisible);
+        
+        if (isVisible && !hasIntersected) {
+          setHasIntersected(true);
+        }
+      },
+      {
+        threshold,
+        rootMargin,
+      }
+    );
+
+    observer.observe(element);
+
+    return () => {
+      observer.unobserve(element);
+    };
+  }, [threshold, rootMargin, hasIntersected]);
+
+  return {
+    elementRef,
+    isVisible: triggerOnce ? hasIntersected : isIntersecting,
+  };
+}