feat: add booking management, Open Day, unified signup modal

- MC registrations: notification toggles (confirm/remind) with urgency
- Group bookings: save to DB from BookingModal, admin CRUD at /admin/bookings
- Open Day: full event system with schedule grid (halls × time), per-class
  booking, discount pricing (30 BYN / 20 BYN from 3+), auto-cancel threshold
- Unified SignupModal replaces 3 separate forms — consistent fields
  (name, phone, instagram, telegram), Instagram DM fallback on network error
- Centralized /admin/bookings page with 3 tabs (classes, MC, Open Day),
  collapsible sections, notification toggles, filter chips
- Unread booking badge on sidebar + dashboard widget with per-type breakdown
- Pricing: contact hint (Instagram/Telegram/phone) on price & rental tabs,
  admin toggle to show/hide
- DB migrations 5-7: group_bookings table, open_day tables, unified fields

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

src/app/admin/layout.tsx

@@ -1,8 +1,9 @@
 "use client";
 
-import { useState } from "react";
+import { useState, useEffect } from "react";
 import Link from "next/link";
 import { usePathname, useRouter } from "next/navigation";
+import { adminFetch } from "@/lib/csrf";
 import {
   LayoutDashboard,
   Sparkles,
@@ -20,6 +21,8 @@ import {
   Menu,
   X,
   ChevronLeft,
+  ClipboardList,
+  DoorOpen,
 } from "lucide-react";
 
 const NAV_ITEMS = [
@@ -30,7 +33,9 @@ const NAV_ITEMS = [
   { href: "/admin/team", label: "Команда", icon: Users },
   { href: "/admin/classes", label: "Направления", icon: BookOpen },
   { href: "/admin/master-classes", label: "Мастер-классы", icon: Star },
+  { href: "/admin/open-day", label: "День открытых дверей", icon: DoorOpen },
   { href: "/admin/schedule", label: "Расписание", icon: Calendar },
+  { href: "/admin/bookings", label: "Записи", icon: ClipboardList },
   { href: "/admin/pricing", label: "Цены", icon: DollarSign },
   { href: "/admin/faq", label: "FAQ", icon: HelpCircle },
   { href: "/admin/news", label: "Новости", icon: Newspaper },
@@ -45,12 +50,27 @@ export default function AdminLayout({
   const pathname = usePathname();
   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}</>;
   }
 
+  // Fetch unread counts — poll every 30s
+  // eslint-disable-next-line react-hooks/rules-of-hooks
+  useEffect(() => {
+    function fetchCounts() {
+      adminFetch("/api/admin/unread-counts")
+        .then((r) => r.json())
+        .then((data: { total: number }) => setUnreadTotal(data.total))
+        .catch(() => {});
+    }
+    fetchCounts();
+    const interval = setInterval(fetchCounts, 30000);
+    return () => clearInterval(interval);
+  }, []);
+
   async function handleLogout() {
     await fetch("/api/logout", { method: "POST" });
     router.push("/admin/login");
@@ -106,6 +126,11 @@ export default function AdminLayout({
               >
                 <Icon size={18} />
                 {item.label}
+                {item.href === "/admin/bookings" && unreadTotal > 0 && (
+                  <span className="ml-auto rounded-full bg-red-500 text-white text-[10px] font-bold min-w-[18px] h-[18px] flex items-center justify-center px-1">
+                    {unreadTotal > 99 ? "99+" : unreadTotal}
+                  </span>
+                )}
               </Link>
             );
           })}