Console polish: Profile action bar, Sessions

Found during Task 7170's visual check (desktop 1440px, local stack). 1. Profile (/profile): the sticky Save bar is a lighter panel spanning only the 480px form, so it reads as a stray box; match the page background or the other editors' bar. 2. Audit › Sessions: the row's mono facts (tokens, duration, ended, node, task, transcript, started) carry no column headers, so "—", "17m", "1h" are cryptic; pass FeedList `columns` as other feeds do. 3. Onboarding widget (FloatingWindow.tsx) still lifts 80px above any form action bar while the Help launcher now sits level with it (Task 7170); seat it consistently or confirm the lift is still needed. Out of scope: the Help launcher seat and Sessions title cap (Task 7170). Done means: - Each item fixed or explicitly rejected with a reason in the PR body. - Visual check at 1440px with screenshots. - `./dc check full` green.

Profile Save bar now uses the page's background; Sessions has sortable column headers; removed FloatingWindow's unused form-bar lift (no remaining caller). Visual check at 1440px done. Quick gate green, lane full gate green, PR #5872 merged (bc79a8f43); its deploy was superseded by later merges. Follow-ups filed as draft Task 7217.