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/styles/radio.css

@@ -18,8 +18,6 @@
   border-radius: 8px;
   background: rgba(2, 15, 20, 0.42);
   box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.035);
-  scrollbar-width: thin;
-  scrollbar-color: rgba(0, 212, 255, 0.46) rgba(255, 255, 255, 0.06);
 }
 #radio-panel .panel-header {
   margin-bottom: 0;
@@ -1092,11 +1090,12 @@ html:not([lang='en']) .data-row-list-text {
 .sdr-radio-card select,
 .sdr-radio-card input[type='number'] {
   min-height: 28px;
-  border: 1px solid rgba(255, 183, 82, 0.28);
   border-radius: 5px;
-  color: #ffd79a;
-  background: rgba(38, 25, 8, 0.52);
   font: 8px/1 var(--font-mono);
+  /* The shared field paints the surface (and the select's chevron). */
+  --gev-field-border-color: rgba(255, 183, 82, 0.28);
+  --gev-field-color: #ffd79a;
+  --gev-field-background: rgba(38, 25, 8, 0.52);
 }
 .sdr-radio-card button {
   padding: 6px 8px;
@@ -1129,7 +1128,7 @@ html:not([lang='en']) .data-row-list-text {
 .sdr-gain-row select {
   flex: 1;
   min-width: 0;
-  padding: 5px 7px;
+  padding: 5px 22px 5px 7px;
 }
 .sdr-adsb-stats {
   display: grid;