Cairn

Pull-request review page in Cairn, showing one branch's description and discussion. Style: flat light, warm paper canvas, white card, teal accent, monospace branch names. Layout: icon rail, banner about the redesigned view, stacked description sections above activity and comments. Components: branch and file chips, stack row, Description/Discussion tabs, summary and test-steps sections, avatar activity events, comment blocks. Vibe: technical, collaborative — code review.