refactor: comprehensive frontend review — consistency, a11y, code quality

- Replace event dispatchers with BookingContext (Hero, Header, FloatingContact)
- Add focus trap hook for modals (SignupModal, NewsModal)
- Extract shared components: CollapsibleSection, ConfirmDialog, PriceField, AdminSkeleton
- Add delete confirmation dialog to ArrayEditor
- Replace hardcoded colors (#050505, #0a0a0a, #c9a96e, #2ecc71) with theme tokens
- Add CSS variables --color-surface-deep/dark for consistent dark surfaces
- Improve contrast: muted text neutral-500 → neutral-400 in dark mode
- Fix modal z-index hierarchy (modals z-60, header z-50, floats z-40)
- Consolidate duplicate formatDate → shared formatting.ts
- Add useMemo to TeamProfile groupMap computation
- Fix typography: responsive price text in Pricing section
- Add ARIA labels/expanded to FAQ, OpenDay, ArrayEditor grip handles
- Hide number input spinners globally
- Reorder admin sidebar: Dashboard → SEO → Bookings → site section order
- Use shared PriceField in Open Day editor
- Fix schedule grid first time slot (09:00) clipped by container
- Fix pre-existing type errors (bookings, hero, db interfaces)

src/app/admin/contact/page.tsx

@@ -1,9 +1,10 @@
 "use client";
 
 import { useState } from "react";
-import { ChevronDown, Plus, X, AlertCircle, Check } from "lucide-react";
+import { Plus, X, AlertCircle, Check } from "lucide-react";
 import { SectionEditor } from "../_components/SectionEditor";
 import { InputField } from "../_components/FormField";
+import { CollapsibleSection } from "../_components/CollapsibleSection";
 import type { ContactInfo } from "@/types/content";
 
 // --- Phone input with mask ---
@@ -160,45 +161,6 @@ function AddressList({ items, onChange }: { items: string[]; onChange: (items: s
   );
 }
 
-// --- Collapsible section ---
-function CollapsibleSection({
-  title,
-  defaultOpen = true,
-  children,
-}: {
-  title: string;
-  defaultOpen?: boolean;
-  children: React.ReactNode;
-}) {
-  const [open, setOpen] = useState(defaultOpen);
-
-  return (
-    <div className="rounded-xl border border-white/10 bg-neutral-900/30 overflow-hidden">
-      <button
-        type="button"
-        onClick={() => setOpen(!open)}
-        className="flex items-center justify-between w-full px-5 py-3.5 text-left cursor-pointer group hover:bg-white/[0.02] transition-colors"
-      >
-        <h3 className="text-sm font-semibold text-neutral-200 group-hover:text-white transition-colors">{title}</h3>
-        <ChevronDown
-          size={16}
-          className={`text-neutral-500 transition-transform duration-200 ${open ? "rotate-180" : ""}`}
-        />
-      </button>
-      <div
-        className="grid transition-[grid-template-rows] duration-300 ease-out"
-        style={{ gridTemplateRows: open ? "1fr" : "0fr" }}
-      >
-        <div className="overflow-hidden">
-          <div className="px-5 pb-5 space-y-4">
-            {children}
-          </div>
-        </div>
-      </div>
-    </div>
-  );
-}
-
 export default function ContactEditorPage() {
   return (
     <SectionEditor<ContactInfo> sectionKey="contact" title="Контакты">