feat: floating contact bar, remove pricing contact links, fix admin hooks

- Add FloatingContact bar (Записаться + Instagram) visible while scrolling
- Hides on hero and near contact section, centered at bottom
- Move BackToTop button up to avoid overlap
- Remove redundant ContactHint from Pricing section (floating bar covers it)
- Fix React hooks order violation in AdminLayout (early return before useEffect)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/app/admin/layout.tsx

@@ -51,15 +51,11 @@ export default function AdminLayout({
   const router = useRouter();
   const [sidebarOpen, setSidebarOpen] = useState(false);
   const [unreadTotal, setUnreadTotal] = useState(0);
-
-  // Don't render admin shell on login page
-  if (pathname === "/admin/login") {
-    return <>{children}</>;
-  }
+  const isLoginPage = pathname === "/admin/login";
 
   // Fetch unread counts — poll every 30s
-  // eslint-disable-next-line react-hooks/rules-of-hooks
   useEffect(() => {
+    if (isLoginPage) return;
     function fetchCounts() {
       adminFetch("/api/admin/unread-counts")
         .then((r) => r.json())
@@ -69,7 +65,12 @@ export default function AdminLayout({
     fetchCounts();
     const interval = setInterval(fetchCounts, 30000);
     return () => clearInterval(interval);
-  }, []);
+  }, [isLoginPage]);
+
+  // Don't render admin shell on login page
+  if (isLoginPage) {
+    return <>{children}</>;
+  }
 
   async function handleLogout() {
     await fetch("/api/logout", { method: "POST" });