feat: notification settings per role + review/unread-msg notifications

- Add notificationSettings JSONB to role_permissions (migration 089)
- sendPushForNotification() — pushes only to users with the notif type enabled
- reviews.ts — push + in-app on new direct and QR reviews
- room-service.ts — use sendPushForNotification('room_service_order')
- publicWidget.ts — push + in-app on new online booking
- jobs.ts — runUnreadMessagesJob() every 15 min, deduped by in-process set
- UsersPage: NOTIFICATION_GROUPS UI in roles tab with per-type toggles
- api.ts / RolePermissionsContext: notificationSettings in types and save()

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

backend/migrations/089_notification_settings.sql

@@ -0,0 +1,4 @@
+-- Migration 089 — Notification settings per role
+
+ALTER TABLE role_permissions
+  ADD COLUMN IF NOT EXISTS notification_settings JSONB NOT NULL DEFAULT '{}'::jsonb;