Keep panel titles inside their cards and scope the hover

Collapsed Recent Imagery (English) and Data Layers (Portuguese) pushed
their toggles out of the card. Collapsed rail launchers now drop the
divider and pack closer, translated collapsed titles use compact type,
and any title that still does not fit ends in an ellipsis.

The hover now matches the dock trays' hover rather than their pinned
look, only on pointers that can hover, and recolours only the hovered
panel's own header, so Radio and body labels keep their colours.

The cyber theme keeps main's gutters and Display toggle size, the dock
and rails share --dock-label-* tokens, and the dimmed open Context title
rule is gone.

changelog.d/1466-panel-chrome-consistency.md

@@ -1,4 +1,5 @@
 - Give the side panels one look. Every panel title now uses the command dock's
-  label type in a brighter colour, collapsed or open; a panel lights up with a
-  blue edge and an accent title on hover, as the dock does; and every collapse
-  button sits the same distance from its panel's edge (asturksever, #1466).
+  label type in a brighter colour; a panel's edge and title light up on hover,
+  as the dock's trays do; and in the default theme each collapse button sits
+  19px from its panel's edge (plus the scrollbar's width in an open, scrolling
+  panel where the system always shows scrollbars) (asturksever, #1466).