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/views/panels/CctvPanel.vue

@@ -28,13 +28,13 @@ const frameData = computed(() =>
 <template>
 <div id="cctv-panel" class="panel-collapsible collapsed" data-panel-id="cctv-panel">
   <div class="panel-glow"></div>
-  <div class="cctv-panel-inner" data-rail-scroller>
+  <div class="cctv-panel-inner ui-scroll" data-rail-scroller>
     <div class="panel-header">
       <span class="panel-title" data-i18n>CCTV</span>
       <span class="panel-divider"></span>
       <button class="panel-collapse-btn" data-collapse-target="cctv-panel" title="Collapse panel" data-i18n-title>+</button>
     </div>
-    <div class="cyber-panel-body" data-rail-scroller>
+    <div class="cyber-panel-body ui-scroll" data-rail-scroller>
     <div id="cctv-frame-wrap" :class="['cctv-frame-wrap', { loading: frame?.wrapLoading, 'has-frame': frame?.hasFrame }]">
       <span class="cctv-frame-caption" aria-hidden="true" data-i18n>ACQUIRING FRAME</span>
       <img id="cctv-frame" alt="CCTV feed frame" :class="{ active: frame?.hasFrame }" :src="frame?.src || undefined" :hidden="live" v-bind="frameData" />