Introducing A new Bitbucket pull request experience

Introduced a new tabular layout for pull requests, moving the activity feed to a prominent 'Overview' tab and creating a dedicated 'Files changed' tab for code review. The activity feed now includes code context for comment threads. The file tree has been moved to the left of the 'Files changed' tab, with an option to collapse it for full-screen code review. The diff view includes familiar options like side-by-side review and hiding whitespace changes, with an option to load files individually for focused review.