Refactor DungeonCanvasViewer for enhanced rendering and object management

- Introduced new rendering methods for various object types including stairs, chests, doors, walls, pots, and sprites, improving visual representation in the dungeon canvas.
- Updated the DrawDungeonCanvas method to streamline object rendering and enhance graphics handling.
- Added detailed layer information overlay to provide context on room objects and sprites.
- Implemented object dimension calculations for walls to ensure accurate rendering based on size properties.
- Improved fallback rendering for objects without valid graphics, enhancing user experience during object placement and editing.

src/app/editor/dungeon/dungeon_editor.cc

@@ -630,12 +630,17 @@ void DungeonEditor::DrawDungeonCanvas(int room_id) {
     // Render background layers with proper positioning
     renderer_.RenderRoomBackgroundLayers(room_id);
 
-    // Render room objects on top of background using the room's palette
+    // Render room objects and sprites with improved graphics
     if (current_palette_id_ < current_palette_group_.size()) {
       auto room_palette = current_palette_group_[current_palette_id_];
+      
+      // Render regular objects with improved fallback
       for (const auto& object : rooms_[room_id].GetTileObjects()) {
         renderer_.RenderObjectInCanvas(object, room_palette);
       }
+      
+      // Render sprites as simple 16x16 squares with labels
+      renderer_.RenderSprites(rooms_[room_id]);
     }
   }