implement a proper consent mode / cookie banner setup

Implement a robust consent mode and cookie banner across the website to ensure compliance for UK and EEA users. Deliverables: display a clear cookie/consent banner to all UK and EEA visitors; allow explicit accept/reject per tracking category; configure Google Consent Mode correctly; ensure GTM, GA4 and Google Ads tags respect consent status dynamically; persist and update consent when users change preferences; ensure consistent behavior across all landing pages and booking flows. Provide reliable, cross-domain and cross-page operation.