feat: booking panel upgrade — refactor, notes, search, manual add, polling

Phase 1 — Refactor:
- Split monolith _shared.tsx into types.ts, BookingComponents, InlineNotes,
  GenericBookingsList, AddBookingModal, SearchBar (no more _ prefix)
- All 3 tabs use GenericBookingsList — shared status workflow, filters, archive

Phase 2 — Features:
- DB migration 13: add notes column to all booking tables
- Inline notes with amber highlight, auto-save 800ms debounce
- Confirm modal comment saves to notes field
- Manual add: 2 tabs (Занятие / Мероприятие), filters expired MCs, Open Day support
- Search bar: cross-table search by name/phone
- 10s polling for real-time updates (bookings page + sidebar badge)
- Status change marks booking as seen (fixes unread count on reset)
- Confirm modal stores human-readable group label instead of raw groupId
- Confirmed group bookings appear in Reminders tab

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

src/app/admin/bookings/McRegistrationsTab.tsx

@@ -0,0 +1,80 @@
+"use client";
+
+import { useState, useEffect, useMemo } from "react";
+import { adminFetch } from "@/lib/csrf";
+import { type BaseBooking, type BookingGroup } from "./types";
+import { LoadingSpinner } from "./BookingComponents";
+import { GenericBookingsList } from "./GenericBookingsList";
+
+interface McRegistration extends BaseBooking {
+  masterClassTitle: string;
+}
+
+interface McSlot { date: string; startTime: string }
+interface McItem { title: string; slots: McSlot[] }
+
+export function McRegistrationsTab() {
+  const [regs, setRegs] = useState<McRegistration[]>([]);
+  const [mcDates, setMcDates] = useState<Record<string, string>>({});
+  const [loading, setLoading] = useState(true);
+
+  useEffect(() => {
+    Promise.all([
+      adminFetch("/api/admin/mc-registrations").then((r) => r.json()),
+      adminFetch("/api/admin/sections/masterClasses").then((r) => r.json()),
+    ]).then(([regData, mcData]: [McRegistration[], { items?: McItem[] }]) => {
+      setRegs(regData);
+      const dates: Record<string, string> = {};
+      const mcItems = mcData.items || [];
+      for (const mc of mcItems) {
+        const latestSlot = mc.slots?.reduce((latest, s) => s.date > latest ? s.date : latest, "");
+        if (latestSlot) dates[mc.title] = latestSlot;
+      }
+      const regTitles = new Set(regData.map((r) => r.masterClassTitle));
+      for (const regTitle of regTitles) {
+        if (dates[regTitle]) continue;
+        for (const mc of mcItems) {
+          const latestSlot = mc.slots?.reduce((latest, s) => s.date > latest ? s.date : latest, "");
+          if (!latestSlot) continue;
+          if (regTitle.toLowerCase().includes(mc.title.toLowerCase()) || mc.title.toLowerCase().includes(regTitle.toLowerCase())) {
+            dates[regTitle] = latestSlot;
+            break;
+          }
+        }
+      }
+      setMcDates(dates);
+    }).catch(() => {}).finally(() => setLoading(false));
+  }, []);
+
+  const today = new Date().toISOString().split("T")[0];
+
+  const groups = useMemo((): BookingGroup<McRegistration>[] => {
+    const map: Record<string, McRegistration[]> = {};
+    for (const r of regs) {
+      if (!map[r.masterClassTitle]) map[r.masterClassTitle] = [];
+      map[r.masterClassTitle].push(r);
+    }
+    return Object.entries(map).map(([title, items]) => {
+      const date = mcDates[title];
+      const isArchived = !date || date < today;
+      return {
+        key: title,
+        label: title,
+        dateBadge: date ? new Date(date + "T12:00").toLocaleDateString("ru-RU", { day: "numeric", month: "short" }) : undefined,
+        items,
+        isArchived,
+      };
+    });
+  }, [regs, mcDates, today]);
+
+  if (loading) return <LoadingSpinner />;
+
+  return (
+    <GenericBookingsList<McRegistration>
+      items={regs}
+      endpoint="/api/admin/mc-registrations"
+      onItemsChange={setRegs}
+      groups={groups}
+    />
+  );
+}