feat: widget rental tab — real objects, time slots, actual rental_bookings

- Add rental_objects to /api/widget/:slug/config response
- Add POST /api/widget/:slug/rental-bookings endpoint with availability check
- Widget rental tab now shows real rental objects (not additionalServices)
- Date picker, hourly or full-day toggle, start/end hour selectors
- Booking submit creates actual rental_booking record in DB
- Success screen shows rental object, date and time slot
- WidgetRentalObject + WidgetRentalBookingPayload types added to api.ts
- BookingWidgetStandalonePage passes rentalObjects to WidgetPreview

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

src/pages/BookingWidgetStandalonePage.tsx

@@ -1,6 +1,6 @@
 import { useState, useEffect } from 'react'
 import { useParams, useSearchParams } from 'react-router-dom'
-import { api, type WidgetRoom, type WidgetCategory } from '../lib/api'
+import { api, type WidgetRoom, type WidgetCategory, type WidgetRentalObject } from '../lib/api'
 import { WidgetPreview, DEFAULT_FORM_FIELDS, DEFAULT_SERVICES } from './BookingWidgetPage'
 import type { WidgetSettings } from './BookingWidgetPage'
 
@@ -8,8 +8,9 @@ export function BookingWidgetStandalonePage() {
   const { slug } = useParams<{ slug: string }>()
   const [searchParams] = useSearchParams()
 
-  const [realRooms, setRealRooms]           = useState<WidgetRoom[]>([])
-  const [realCategories, setRealCategories] = useState<WidgetCategory[]>([])
+  const [realRooms, setRealRooms]                 = useState<WidgetRoom[]>([])
+  const [realCategories, setRealCategories]       = useState<WidgetCategory[]>([])
+  const [realRentalObjects, setRealRentalObjects] = useState<WidgetRentalObject[]>([])
   const [paymentEnabled, setPaymentEnabled] = useState<boolean | undefined>(undefined)
   const [settings, setSettings] = useState<WidgetSettings>({
     hotelName:       '',
@@ -34,6 +35,7 @@ export function BookingWidgetStandalonePage() {
       .then(config => {
         setRealRooms(config.rooms ?? [])
         setRealCategories(config.categories ?? [])
+        setRealRentalObjects(config.rentalObjects ?? [])
         setPaymentEnabled(config.paymentEnabled)
         if (config.widgetSettings) {
           const ws = config.widgetSettings
@@ -64,6 +66,7 @@ export function BookingWidgetStandalonePage() {
           slug={slug}
           realRooms={realRooms.length > 0 ? realRooms : undefined}
           realCategories={realCategories.length > 0 ? realCategories : undefined}
+          realRentalObjects={realRentalObjects.length > 0 ? realRentalObjects : undefined}
           paymentEnabled={paymentEnabled}
         />
       </div>