This fixes an issue where viewport-fit=cover and black-translucent statusbar
configuration allowed content to extend under the iOS statusbar. Added env(safe-area-inset-top)
CSS handling to all main layout components:
- SessionHeader with pt-[env(safe-area-inset-top)]
- SessionsPage, MachinesPage, SpawnPage with safe-area padding
- FilesPage and FilePage headers with safe-area padding