fix: add SSR-safe ScrollFadeIn component for scroll animations

ScrollFadeIn uses IntersectionObserver + CSS transitions instead of
Framer Motion's initial prop. Key difference: no inline style in SSR
HTML, so content is visible by default. Animation only activates
after client hydration (hasMounted check).

Wraps About, Projects, Contact, Footer in HomePageServer.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

app/components/ScrollFadeIn.tsx

@@ -0,0 +1,54 @@
+"use client";
+
+import { useRef, useEffect, useState, type ReactNode } from "react";
+
+interface ScrollFadeInProps {
+  children: ReactNode;
+  className?: string;
+  delay?: number;
+}
+
+/**
+ * Wraps children in a fade-in-up animation triggered by scroll.
+ * Unlike Framer Motion's initial={{ opacity: 0 }}, this does NOT
+ * render opacity:0 in SSR HTML — content is visible by default
+ * and only hidden after JS hydration for the animation effect.
+ */
+export default function ScrollFadeIn({ children, className = "", delay = 0 }: ScrollFadeInProps) {
+  const ref = useRef<HTMLDivElement>(null);
+  const [isVisible, setIsVisible] = useState(false);
+  const [hasMounted, setHasMounted] = useState(false);
+
+  useEffect(() => {
+    setHasMounted(true);
+    const el = ref.current;
+    if (!el) return;
+
+    const observer = new IntersectionObserver(
+      ([entry]) => {
+        if (entry.isIntersecting) {
+          setIsVisible(true);
+          observer.unobserve(el);
+        }
+      },
+      { threshold: 0.1 }
+    );
+
+    observer.observe(el);
+    return () => observer.disconnect();
+  }, []);
+
+  return (
+    <div
+      ref={ref}
+      className={className}
+      style={hasMounted ? {
+        opacity: isVisible ? 1 : 0,
+        transform: isVisible ? "translateY(0)" : "translateY(30px)",
+        transition: `opacity 0.6s ease ${delay}s, transform 0.6s ease ${delay}s`,
+      } : undefined}
+    >
+      {children}
+    </div>
+  );
+}