feat: about stats cards, pricing popular badge, back-to-top button

- About: add 3 stat cards (13 trainers, 6 styles, 2 locations)
- Pricing: highlight first plan with gold "Популярный" badge
- BackToTop: floating gold button appears after 600px scroll

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

src/components/sections/About.tsx

@@ -1,7 +1,14 @@
+import { Users, Layers, MapPin } from "lucide-react";
 import { siteContent } from "@/data/content";
 import { SectionHeading } from "@/components/ui/SectionHeading";
 import { Reveal } from "@/components/ui/Reveal";
 
+const stats = [
+  { icon: <Users size={22} />, value: "13", label: "тренеров" },
+  { icon: <Layers size={22} />, value: "6", label: "направлений" },
+  { icon: <MapPin size={22} />, value: "2", label: "зала в Минске" },
+];
+
 export function About() {
   const { about } = siteContent;
 
@@ -22,6 +29,28 @@ export function About() {
             </Reveal>
           ))}
         </div>
+
+        {/* Stats */}
+        <Reveal>
+          <div className="mx-auto mt-14 grid max-w-3xl grid-cols-3 gap-4 sm:gap-8">
+            {stats.map((stat, i) => (
+              <div
+                key={i}
+                className="group flex flex-col items-center gap-3 rounded-2xl border border-neutral-200 bg-white/50 p-6 transition-all duration-300 hover:border-[#c9a96e]/30 sm:p-8 dark:border-white/[0.06] dark:bg-white/[0.02] dark:hover:border-[#c9a96e]/20"
+              >
+                <div className="flex h-11 w-11 items-center justify-center rounded-xl bg-[#c9a96e]/10 text-[#a08050] transition-colors group-hover:bg-[#c9a96e]/20 dark:text-[#d4b87a]">
+                  {stat.icon}
+                </div>
+                <span className="font-display text-3xl font-bold text-neutral-900 sm:text-4xl dark:text-white">
+                  {stat.value}
+                </span>
+                <span className="text-sm text-neutral-500 dark:text-neutral-400">
+                  {stat.label}
+                </span>
+              </div>
+            ))}
+          </div>
+        </Reveal>
       </div>
     </section>
   );