Every column is sized to its own content (no fixed slots, no flex:1 filler, no dead gap). The ATOM grows
as wide as it needs and no wider, sitting left-aligned in its POD. Drag the right edge of the POD to
narrow it. When the ATOM can't fit, columns collapse in priority order — physical types → venact type codes →
expressions → column names — each truncating until gone before the next yields. Column names truncate last and
never disappear. Editable: click any output name or expression and type — the layout re-flows
live (grows into free POD space, or forces a collapse if there's none left).