Add animated mesh gradient hero with overlay content

- Add @paper-design/shaders for WebGL mesh gradient effect
- Create hero-shader.js with liquid ink gradient (grayscale palette)
- Add overlay content: title, tagline, and CTA on shader
- Update hero section structure and styling
- Fix accessibility: gallery dot buttons, toggle ARIA attributes
- Fix undefined --color-terracotta CSS variable
- Update distribution structure for Codex/Cursor skills

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

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

public/js/utils/scroll.js

@@ -90,9 +90,13 @@ export function initHashTracking() {
 			}
 		});
 
-		if (activeSection && activeSection !== currentHash) {
+		if (activeSection !== currentHash) {
 			currentHash = activeSection;
-			history.replaceState(null, '', `#${activeSection}`);
+			if (activeSection) {
+				history.replaceState(null, '', `#${activeSection}`);
+			} else {
+				history.replaceState(null, '', window.location.pathname);
+			}
 		}
 
 		ticking = false;