Replace custom header with PageWrapper inline fullHeight and add
Popconfirm to the stop action. The nav-only-tabs content-split hack is
preserved; WebSocket session, rerun, and list logic untouched.
Extract the standard form drawer (width 640, footer actions, destroyOnClose)
as FormDrawer; reuse existing usePolling hook. IntelligentEvals becomes the
first consumer — create drawer and both 5s pollings switched with zero
behaviour change. Includes ui-consistency spec, tickets, and ADR-0005.