Add GSAP scroll-reveal animations (self-hosted, respects reduced motion)

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LSDgjk1Agjy9Z2UH2n8bc3

index.html

@@ -1061,3 +1061,6 @@ footer.note{
   renderAll();
 })();
 </script>
+<script src="vendor/gsap.min.js"></script>
+<script src="vendor/ScrollTrigger.min.js"></script>
+<script src="animations.js"></script>