Domain visibility for multi-site setups

Running multiple sites on a shared web integration now allows visibility into which domain each session originated from. The page.url.domainCopy attribute surfaces in three locations:

1. Session list sidebar — Domain displays alongside location and browser information for quick identification
2. Session detail page — Domain appears in the header while reviewing page views and events
3. Dashboard filters — New Domain filter variable available in Overview and Web Vitals dashboards for network-wide metrics segmentation

Additional improvements: Session detail header items now wrap gracefully on smaller screens rather than becoming compressed.