A rail row stands 32 tall with its icon in the text's colour, and a text-only row keeps the icon's slot

[WaylandYang]

Rail rows, measured against the Review rail:

• the icon takes the text's colour (it was pinned to ink-3, so a selected row's icon stayed dim);
• a nav row is 32 tall (py 6, was 8) and rows sit 2 apart — u-rail-list, defined once in styles.css because 2 is off the spacing ladder;
• groups, and a control above a list, sit 4 apart (Review's Overview gap was 8, Ontology's filter/schema/segmented gaps were 8/8/12);
• a text-only row keeps the icon's slot, so labels line up whether or not a row has an icon (Review's queues, Chat's conversations);
• the Danger zone entry is warn, not danger: it only leads there; the delete button inside stays red. Row gets a tone prop for it.