feat: add live V2X Cesium preview overlay

scripts/lib/cesium-preview.css

@@ -161,6 +161,74 @@ body.scene-error .loading-bar span {
   white-space: pre-line;
 }
 
+#v2xPanel {
+  position: absolute;
+  right: 12px;
+  bottom: 12px;
+  z-index: 2;
+  box-sizing: border-box;
+  width: min(300px, calc(100vw - 24px));
+  padding: 10px 12px;
+  border-radius: 4px;
+  background: rgba(20, 24, 28, 0.88);
+  color: #fff;
+  font-size: 12px;
+  line-height: 1.45;
+  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.22);
+}
+
+.v2x-heading {
+  display: grid;
+  gap: 2px;
+  margin-bottom: 8px;
+}
+
+.v2x-heading span,
+#v2xStatus {
+  color: rgba(255, 255, 255, 0.68);
+}
+
+#v2xLoginForm,
+#v2xLiveControls {
+  display: grid;
+  gap: 7px;
+}
+
+#v2xPanel label {
+  display: grid;
+  gap: 3px;
+}
+
+#v2xPanel input {
+  box-sizing: border-box;
+  width: 100%;
+  height: 27px;
+  border: 1px solid rgba(255, 255, 255, 0.28);
+  border-radius: 3px;
+  padding: 0 7px;
+  background: rgba(255, 255, 255, 0.12);
+  color: #fff;
+  font: inherit;
+}
+
+#v2xPanel button {
+  height: 27px;
+  margin-right: 6px;
+  border: 0;
+  border-radius: 3px;
+  padding: 0 8px;
+  background: #e9f3f5;
+  color: #112326;
+  font: inherit;
+  cursor: pointer;
+}
+
+#v2xStatus {
+  display: block;
+  margin-top: 8px;
+  overflow-wrap: anywhere;
+}
+
 #vehicleInfoCard {
   left: 0;
   top: 0;