feat(ui): refine live observation workspace

apps/control-station/src/App.tsx

@@ -137,6 +137,14 @@ export default function App() {
     runtime.state?.observationSources ?? [],
     runtime.setObservationSourceActive,
   );
+  const focusedObservationSource = runtime.state?.observationSources?.find(
+    (source) => source.id === observationLayout.focusedSourceId,
+  );
+  const observationFullscreenActive = Boolean(
+    activeDefinition?.kind === "spatial"
+      ? observationLayout.maximizedFloatingSourceId || focusedObservationSource?.modality === "point-cloud"
+      : activeDefinition?.kind === "cameras" && focusedObservationSource,
+  );
 
   useEffect(() => {
     const remote = runtime.state?.viewerSettings;
@@ -290,6 +298,7 @@ export default function App() {
       <ApplicationShell
         data-nodedc-ui
         className="control-station"
+        data-observation-fullscreen={observationFullscreenActive ? "true" : undefined}
         navigationOpen={workspace.navigationOpen && activeRoot !== null}
         contentOpen={workspace.contentOpen && activeDefinition !== null}
         contentExpanded={workspace.contentExpanded}