feat(editor): add entity operations for overworld editing

- Introduced new `entity_operations.cc` and `entity_operations.h` files to handle the insertion of entrances, exits, sprites, and items in the overworld editor.
- Updated `map_properties.cc` to include a context menu for entity insertion, allowing users to add various entities directly from the canvas.
- Enhanced `overworld_editor.cc` to manage entity insertion callbacks and streamline the editing process.

Benefits:
- Improves the functionality of the overworld editor by enabling direct manipulation of entities.
- Provides a more intuitive user experience with context-sensitive menus for entity operations.

src/app/gui/canvas/canvas_interaction_handler.h

@@ -8,7 +8,6 @@
 
 namespace yaze {
 namespace gui {
-namespace canvas {
 
 /**
  * @brief Tile interaction mode for canvas
@@ -201,7 +200,6 @@ class CanvasInteractionHandler {
   bool IsMouseReleased(ImGuiMouseButton button);
 };
 
-}  // namespace canvas
 }  // namespace gui
 }  // namespace yaze