feat(ui): give every panel one scrollbar, select and slider skin

Every scrolling surface carries the kit's .ui-scroll, which
draws the thin themed scrollbar from --scroll-thumb and --scroll-track; the
Context panel and others drew the platform's light scrollbar because the
page declares no dark color-scheme. The per-panel scrollbar rules go; Cyber
sets the two tokens and Cockpit's HUD windows keep their accent tint.

Selects draw .gev-field's own chevron instead of the platform arrow, the
voice selects join .gev-field, number fields keep dark spinners, and the
Street Level range uses the shared slider in its green.

src/ui/recentImagery/RecentImageryReadout.vue

@@ -54,7 +54,10 @@ defineProps({
       ></div
     ><div
       id="ri-strip"
-      :class="['ri-block ri-strip', { searching: view.strip.searching }]"
+      :class="[
+        'ri-block ri-strip ui-scroll',
+        { searching: view.strip.searching },
+      ]"
       tabindex="0"
       role="listbox"
       aria-orientation="horizontal"