refactor(editor): streamline ImGui card management across various editors

- Refactored multiple editor classes to ensure that ImGui::End() is always called after ImGui::Begin(), enhancing state management and preventing potential rendering issues.
- Updated the DungeonEditor, GraphicsEditor, ScreenEditor, MessageEditor, MusicEditor, and SpriteEditor to follow this pattern, improving code consistency and reliability.

Benefits:
- Improves the stability of the editor UI by ensuring proper handling of ImGui state.
- Enhances code readability and maintainability by standardizing the usage of ImGui functions across different editor components.

src/app/editor/graphics/graphics_editor.cc

@@ -112,28 +112,29 @@ absl::Status GraphicsEditor::Update() {
   prototype_card.SetDefaultSize(600, 500);
 
   // Get visibility flags from card manager and pass to Begin()
+  // Always call End() after Begin() - End() handles ImGui state safely
   if (sheet_editor_card.Begin(card_manager.GetVisibilityFlag("graphics.sheet_editor"))) {
     status_ = UpdateGfxEdit();
-    sheet_editor_card.End();
   }
+  sheet_editor_card.End();
 
   if (sheet_browser_card.Begin(card_manager.GetVisibilityFlag("graphics.sheet_browser"))) {
     if (asset_browser_.Initialized == false) {
       asset_browser_.Initialize(gfx::Arena::Get().gfx_sheets());
     }
     asset_browser_.Draw(gfx::Arena::Get().gfx_sheets());
-    sheet_browser_card.End();
   }
+  sheet_browser_card.End();
 
   if (player_anims_card.Begin(card_manager.GetVisibilityFlag("graphics.player_animations"))) {
     status_ = UpdateLinkGfxView();
-    player_anims_card.End();
   }
+  player_anims_card.End();
 
   if (prototype_card.Begin(card_manager.GetVisibilityFlag("graphics.prototype_viewer"))) {
     status_ = UpdateScadView();
-    prototype_card.End();
   }
+  prototype_card.End();
 
   CLEAR_AND_RETURN_STATUS(status_)
   return absl::OkStatus();

src/app/editor/graphics/screen_editor.cc

@@ -109,30 +109,29 @@ absl::Status ScreenEditor::Update() {
   naming_screen_card.SetDefaultSize(500, 400);
 
   // Get visibility flags from card manager and pass to Begin()
+  // Always call End() after Begin() - End() handles ImGui state safely
   if (dungeon_maps_card.Begin(card_manager.GetVisibilityFlag("screen.dungeon_maps"))) {
     DrawDungeonMapsEditor();
   }
   dungeon_maps_card.End();
-
+  
   if (inventory_menu_card.Begin(card_manager.GetVisibilityFlag("screen.inventory_menu"))) {
     DrawInventoryMenuEditor();
-  
   }
   inventory_menu_card.End();
-
+  
   if (overworld_map_card.Begin(card_manager.GetVisibilityFlag("screen.overworld_map"))) {
     DrawOverworldMapEditor();
   }
   overworld_map_card.End();
-
+  
   if (title_screen_card.Begin(card_manager.GetVisibilityFlag("screen.title_screen"))) {
     DrawTitleScreenEditor();
-  
   }
   title_screen_card.End();
-
+  
   if (naming_screen_card.Begin(card_manager.GetVisibilityFlag("screen.naming_screen"))) {
-    DrawNamingScreenEditor();  
+    DrawNamingScreenEditor();
   }
   naming_screen_card.End();