feat: BLACK HEART DANCE HOUSE landing page

Landing page with Hero, About, Team, Classes, and Contact sections.
Light/dark mode, scroll reveal animations, Yandex Maps, responsive design.
Next.js 16 + Tailwind v4 + TypeScript.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

.eslintrc.json

@@ -0,0 +1,3 @@
+{
+  "extends": ["next/core-web-vitals", "prettier"]
+}