fix: standalone /book page applies saved widget settings from backend

BookingWidgetStandalonePage now fetches widgetSettings from the public
config API and applies them (color, language, mode, etc.) instead of
always falling back to URL param defaults. URL params still work as
overrides if present.

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

src/lib/api.ts

@@ -1655,6 +1655,17 @@ export interface WidgetConfig {
   currency: string
   rooms: WidgetRoom[]
   categories: WidgetCategory[]
+  widgetSettings?: {
+    primaryColor: string
+    language: string
+    roomDisplayMode: string
+    minNights: number
+    showRental: boolean
+    showPromo: boolean
+    allowExtraBeds: boolean
+    allowChildren: boolean
+    hotelName: string
+  }
 }
 
 export interface WidgetBookingPayload {