Implemented new C++ logic

Client/streamhub/PlotPanel.h

@@ -0,0 +1,19 @@
+/**
+ * @file PlotPanel.h
+ * @brief ImPlot-based oscilloscope plot panel.
+ */
+
+#pragma once
+
+namespace StreamHubClient {
+class App;
+
+/**
+ * @brief Render one oscilloscope plot panel.
+ * @param app      Application state.
+ * @param plotIdx  Which slot in app.plotSlots() to render.
+ * @param paused   Whether data updates are paused for this plot.
+ */
+void RenderPlotPanel(App& app, int plotIdx, bool& paused);
+
+} /* namespace StreamHubClient */