1.9.1

v1.9.1: fix cards showing through the panel header while scrolling

The header was position:sticky inside a single scrolling view, which let cards
render over/through it during scroll momentum. Switch to a flex column: a fixed
header (flex:0 0 auto) plus the card list as its own scroll area
(flex:1; min-height:0; overflow-y:auto), so cards can never paint outside the list.