fix: remove floating booking button overlapping mobile menu, center Open Day heading

- Remove floating "Записаться" button that covered hamburger menu on mobile scroll
- Booking still accessible via mobile menu dropdown and Hero CTA
- Center Open Day section heading to match all other sections

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

src/components/layout/Header.tsx

@@ -180,16 +180,6 @@ export function Header() {
         </nav>
       </div>
 
-      {/* Floating booking button — visible on scroll, mobile */}
-      <button
-        onClick={() => setBookingOpen(true)}
-        aria-label="Записаться"
-        className={`fixed bottom-6 right-6 z-40 flex items-center gap-2 rounded-full bg-gold px-5 py-3 text-sm font-semibold text-black shadow-lg shadow-gold/25 transition-all duration-500 hover:bg-gold-light hover:shadow-xl hover:shadow-gold/30 cursor-pointer lg:hidden ${
-          scrolled ? "translate-y-0 opacity-100" : "translate-y-16 opacity-0 pointer-events-none"
-        }`}
-      >
-        Записаться
-      </button>
 
       <SignupModal open={bookingOpen} onClose={() => setBookingOpen(false)} endpoint="/api/group-booking" />
     </header>

src/components/sections/OpenDay.tsx

@@ -49,7 +49,7 @@ export function OpenDay({ data }: OpenDayProps) {
     <section id="open-day" className="py-10 sm:py-14">
       <div className="mx-auto max-w-6xl px-4">
         <Reveal>
-          <SectionHeading>{event.title}</SectionHeading>
+          <SectionHeading centered>{event.title}</SectionHeading>
         </Reveal>
 
         <Reveal>