The m4 scene plumbing was already honest — one WindowGroup value per
CardWindowRef enforces one-window-per-card, and CardWindowFate's
ancestor walk answered dismissal — so this card fills the window: a
two-column shell whose body column takes all resize flex and whose
sidebar width derives once from font metrics (26 characters of average
body advance plus em gutters), the five 05-ordered section headers as
placeholders, and the card body as selectable plain text until Preview
mode lands. The fate walk now returns a CardPlacement (card + lane), so
one pass answers both liveness and the live board › lane subtitle; a
board rename lands for free through displayName. Card windows remember
their frames per card in the board record (case-folded id keys,
unchanged-writes-nothing), restoring instead of cascading; only
unremembered cards take the last-used size and cascade. Store
acquisition stays gated on liveStore — a card window never opens a
board — and the close-flush hook stands with nothing to flush until the
Edit-session card.
Claude-Session: https://claude.ai/code/session_01SR4XGjmBE16ZUYWpfFHXwY
