feat: centralized payment gateways + booking widget API

Backend:
- Migration 065: hotel_payment_gateways table (migrates YooKassa from deposit_settings)
- online_bookings table for widget submissions
- Routes: CRUD /api/hotels/:slug/payment-gateways
- Public widget API: /api/widget/:slug/{config,availability,bookings}
- yookassa.ts: add createCharge() for immediate capture

Frontend:
- PaymentSettingsPage: add 'Онлайн-оплата' section with gateway CRUD and module toggles
- DepositSettingsPage: replace YooKassa fields with link to centralized settings
- BookingWidgetPage: connect to real API, show gateway status, real booking submit
- api.ts: add PaymentGateway types, paymentGateways and widget API methods

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

backend/src/app.ts

@@ -43,6 +43,8 @@ import minibarRoutes from './routes/minibar'
 import depositRoutes from './routes/deposit'
 import paymentsRoutes from './routes/payments'
 import paymentMethodsRoutes from './routes/paymentMethods'
+import paymentGatewaysRoutes from './routes/paymentGateways'
+import publicWidgetRoutes from './routes/publicWidget'
 import { setupAgentWsRoute } from './agent-ws'
 import { startJobs } from './jobs'
 
@@ -138,6 +140,8 @@ export async function buildApp() {
   await fastify.register(depositRoutes)
   await fastify.register(paymentsRoutes)
   await fastify.register(paymentMethodsRoutes)
+  await fastify.register(paymentGatewaysRoutes)
+  await fastify.register(publicWidgetRoutes)
   await fastify.register(setupAgentWsRoute)
 
   startJobs()