feat: notifications API, auto-jobs, calendar housekeeping fixes

Backend:
- notifications table (024 migration) — stores per-hotel notifications
- GET/PATCH/POST/DELETE /api/hotels/:slug/notifications endpoints
- createNotification() helper used by jobs + future hooks
- jobs.ts — background tasks every 10min: auto-cancel no-shows and
  auto-checkout overdue stays based on hotel_settings, broadcasts WS
  events and creates notifications for each automated action

Frontend:
- CalendarPage: handle housekeeping_done WS → update room status in
  calendar in real-time (bug fix)
- CalendarPage: when manually setting room to dirty via context menu,
  auto-create housekeeping task and broadcast via WS (bug fix)
- NotificationsContext: replaced mock data with real API integration,
  polls every 60s, syncs markRead/delete to backend
- SettingsPage booking section: auto-cancel no-show toggle + hours
  selector; auto-checkout toggle + hours selector
- api.ts: notifications API methods
- useHotelSocket: notification:new WS message type

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

backend/src/app.ts

@@ -29,6 +29,8 @@ import ratePeriodsRoutes   from './routes/rate-periods'
 import rateOverridesRoutes from './routes/rate-overrides'
 import uploadRoutes        from './routes/upload'
 import housekeepingSettingsRoutes from './routes/housekeeping-settings'
+import notificationsRoutes from './routes/notifications'
+import { startJobs } from './jobs'
 
 export async function buildApp() {
   const fastify = Fastify({
@@ -102,6 +104,9 @@ export async function buildApp() {
   await fastify.register(rateOverridesRoutes)
   await fastify.register(uploadRoutes)
   await fastify.register(housekeepingSettingsRoutes)
+  await fastify.register(notificationsRoutes)
+
+  startJobs()
 
   return fastify
 }