Initial commit: HotelSync PMS v0.1.0

- React 18 + TypeScript + Vite + Tailwind CSS
- Шахматка бронирований (drag-to-book)
- Страницы: Calendar, Bookings, Rooms, Housekeeping, Channels, API Docs, Settings
- Роли: super_admin, hotel_manager, housekeeper
- Светлая/тёмная тема
- Docker + Nginx конфигурация
- Лендинг hotelsync.ru

src/contexts/ThemeContext.tsx

@@ -0,0 +1,42 @@
+import { createContext, useContext, useEffect, useState } from 'react'
+
+type Theme = 'light' | 'dark'
+
+interface ThemeContextValue {
+  theme: Theme
+  toggle: () => void
+}
+
+const ThemeContext = createContext<ThemeContextValue | null>(null)
+
+export function ThemeProvider({ children }: { children: React.ReactNode }) {
+  const [theme, setTheme] = useState<Theme>(() => {
+    const stored = localStorage.getItem('hotelsync-theme') as Theme | null
+    if (stored) return stored
+    return window.matchMedia('(prefers-color-scheme: dark)').matches ? 'dark' : 'light'
+  })
+
+  useEffect(() => {
+    const root = document.documentElement
+    if (theme === 'dark') {
+      root.classList.add('dark')
+    } else {
+      root.classList.remove('dark')
+    }
+    localStorage.setItem('hotelsync-theme', theme)
+  }, [theme])
+
+  const toggle = () => setTheme(t => t === 'light' ? 'dark' : 'light')
+
+  return (
+    <ThemeContext.Provider value={{ theme, toggle }}>
+      {children}
+    </ThemeContext.Provider>
+  )
+}
+
+export function useTheme() {
+  const ctx = useContext(ThemeContext)
+  if (!ctx) throw new Error('useTheme must be used within ThemeProvider')
+  return ctx
+}