- Replace AR Hero gradient + standalone Revenue YTD with 4 KpiCardMobile tiles (2x2 grid)
- Drop bar chart; add monthly-revenue stacked list (D-09 / DASH-04 precedent)
- Add shadcn Collapsible for Open Invoices and Recent Payments (D-15, D-16)
- Aging row uses locked amber/orange/destructive palette (D-08)
- Top AR by Customer rendered as stacked list with proportion bars (D-07)
- toast.success + toast.error on sync outcomes (D-17, D-18)
- FinanceSkeleton on initial load; destructive retry card on error (D-17, D-18)
- D-19 empty state when total_ar===0 and open_invoices.length===0
- D-23: no page H1; header controls row with aria-labels (D-14)
- No font-medium, no font-bold, no raw red/yellow/green Tailwind classes