The active tilemap layer can be renamed from the painting section, and a Show setting fades or hides the other layers in the scene view while the tilemap is selected (#138)

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

src/editor/state.ts

@@ -146,10 +146,18 @@ function pickIds(input: readonly string[], primary?: string): { ids: string[]; p
  */
 export type TilemapTool = 'select' | 'brush' | 'erase' | 'rect';
 
+/**
+ * How the scene view shows the layers of the selected tilemap next to the one painted on (#138):
+ * all as they are, the others faded, or the painted one alone. A way of looking while painting,
+ * so it leaves the model – and with it the game – untouched.
+ */
+export type TilemapFocus = 'all' | 'dim' | 'solo';
+
 export interface TilemapPaint {
   tool: TilemapTool;
   tileId: string;
   layerId: string;
+  focus: TilemapFocus;
 }
 
 export type EditorMode = 'edit' | 'play';
@@ -202,7 +210,7 @@ export class EditorState {
    * on. Editor state, not model state – like the picked tile of the Animation tab, it is a way of
    * working rather than something the project remembers.
    */
-  tilemapPaint: TilemapPaint = { tool: 'select', tileId: '', layerId: '' };
+  tilemapPaint: TilemapPaint = { tool: 'select', tileId: '', layerId: '', focus: 'all' };
   /** The real (saved) model and its undo stack while `project` is the play-mode copy. */
   private edit: { project: Project; commands: CommandStack } | null = null;