feat(bookings): implement booking system and confirmation flow

Add database tables and repository for managing bookings
Create API endpoints for booking submission and capacity management
Update landing page to persist bookings before WhatsApp redirection

server/utils/app-url.ts

@@ -0,0 +1,18 @@
+import type { H3Event } from 'h3'
+
+import { getRequestURL } from 'h3'
+
+export function getAppOrigin(event: H3Event) {
+  const config = useRuntimeConfig()
+
+  if (config.public.appUrl) {
+    return new URL(config.public.appUrl).origin
+  }
+
+  const url = getRequestURL(event)
+  return `${url.protocol}//${url.host}`
+}
+
+export function buildAppUrl(event: H3Event, path: string) {
+  return new URL(path, getAppOrigin(event)).toString()
+}