Add Availability Calendar, Modules system, and route refactoring

- Add AvailabilityPage with price grid (categories × dates), drag-select,
  channel prices, EditPanel, PeriodModal, and rate periods tab
- Add ModulesContext with localStorage persistence and dynamic sidebar items
- Add ModulesPage with WiFi Auth, Payments, TV Welcome, Smart Locks,
  OLAP Reports, Website Builder, Booking Widget modules
- Add ReportsPage (OLAP analytics with KPI cards, charts, tables)
- Add WebsitePage and BookingWidgetPage placeholders
- Remove hotel slug from URL routing; hotel context from JWT
- Add Доступность nav item in Sidebar under Управление
- Fix LoginPage redirects and HotelSync branding

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/contexts/AuthContext.tsx

@@ -5,7 +5,7 @@ import { MOCK_USERS } from '../data/mockData'
 interface AuthContextValue {
   session: AuthSession | null
   user: User | null
-  login: (email: string, password: string) => Promise<boolean>
+  login: (email: string, password: string) => Promise<User | null>
   logout: () => void
 }
 
@@ -17,15 +17,15 @@ export function AuthProvider({ children }: { children: React.ReactNode }) {
     return stored ? JSON.parse(stored) : null
   })
 
-  const login = async (email: string, _password: string): Promise<boolean> => {
+  const login = async (email: string, _password: string): Promise<User | null> => {
     // Mock authentication — in production, call POST /auth/login
     await new Promise(r => setTimeout(r, 800))
     const user = MOCK_USERS.find(u => u.email.toLowerCase() === email.toLowerCase())
-    if (!user) return false
+    if (!user) return null
     const s: AuthSession = { user, token: 'mock-jwt-token-' + user.id }
     setSession(s)
     sessionStorage.setItem('hotelsync-session', JSON.stringify(s))
-    return true
+    return user
   }
 
   const logout = () => {