Author the general and paintings panels in the paint HUD

Add the General and Paintings panels to the HUD layout prefab and register
their stable widget names so the binder can find and manage them.

Assets/Scripts/PaintHud.cs

@@ -37,12 +37,14 @@ public partial class PaintHud : MonoBehaviour
     public GameObject layoutPrefab;
 
     // Stable widget names shared by the code-gen builder, the baked prefab and the binder.
+    private const string PanelGeneral = "Panel_General";
     private const string PanelSpray = "Panel_Spray";
     private const string PanelAlbedo = "Panel_Albedo";
     private const string PanelMetallicSmoothness = "Panel_MetallicSmoothness";
     private const string PanelOcclusion = "Panel_Occlusion";
     private const string PanelEmission = "Panel_Emission";
     private const string PanelBrushSize = "Panel_BrushSize";
+    private const string PanelPaintings = "Panel_Paintings";
     private const string ToggleAlbedo = "Toggle_Albedo";
     private const string ToggleMetallicSmoothness = "Toggle_MetallicSmoothness";
     private const string ToggleOcclusion = "Toggle_Occlusion";
@@ -79,7 +81,9 @@ public partial class PaintHud : MonoBehaviour
         PanelOcclusion,
         PanelEmission,
         PanelBrushSize,
-        PanelSpray
+        PanelSpray,
+        PanelGeneral,
+        PanelPaintings
     };
 
     private GameObject _panel;