Implement Godot UX scene scaffold

src/ReactorMaintenance.Godot/Controls/CellInspector.cs

@@ -0,0 +1,15 @@
+using Godot;
+
+namespace ReactorMaintenance.Godot.Controls;
+
+public partial class CellInspector : PanelContainer
+{
+    public override void _Ready()
+    {
+        AddChild(m_Text);
+        m_Text.Text = "Selected Cell: 0,0\nTerrain: service floor\nProp: none\nHazards: none\nUnderground: hidden";
+        m_Text.AutowrapMode = TextServer.AutowrapMode.WordSmart;
+    }
+
+    private readonly Label m_Text = new();
+}