Enabled switch, text assets, mouse input and the jump-and-run example game

Engine additions that the example game needed:
- `enabled` as a shared property of every placeable asset (default on, an
  override on the scene object). A switched-off object is not drawn, does not
  collide and its behavior does not run - and neither does anything parented
  below it. Disabled objects are now hidden in the scene view as well, so the
  editor shows what the game shows; they stay in the hierarchy panel, which is
  where they are selected and switched back on.
- Asset type `text` (text, fontSize, color, align), rendered in scene and game.
- Pointer input in the game view: `On click`, `Mouse position`, `Mouse button`,
  `Is hovered`, hit-tested against colliders, else sprite/text footprints.
- New nodes: Set/Is enabled, Set text, Is asset, Name of, Equals, To text,
  Join text, Floor/Ceil/Round, Modulo, Random, Time, Restart game.

Tooling: shared CDP harness (tools/harness.mjs), central project registry with
a guard that keeps destructive scripts off the playground (tools/projects.mjs),
plus smoke suites for the demo scene and the jump-and-run game.

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

src/editor/App.ts

@@ -69,6 +69,8 @@ function installDebugHook(app: Application, state: EditorState, editor: Editor):
     drawOrder: () => viewport.drawOrder(),
     /** Screen position of an object in the Scene tab (its world position through the view). */
     objectScreen: (id: string) => viewport.objectScreen(id),
+    /** The same for the Game tab (through the camera), so tests can click what the player sees. */
+    gameScreen: (id: string) => gameView.objectScreen(id),
     graph: {
       current: () => graphEditor.currentAssetId,
       portAt: (nodeId: string, port: string, isOutput: boolean) => graphEditor.portGlobal(nodeId, port, isOutput),
@@ -320,6 +322,12 @@ class Editor {
       this.stop();
       return;
     }
+    // Restart game: throw the run away and start the scene again from the saved model.
+    if (world.restartRequested) {
+      this.stop();
+      this.play();
+      return;
+    }
     // Mirror what the systems did into the runtime copy so the panels show live values.
     // A destroyed entity removes its object – that is a structural change the lists must see.
     if (world.syncToModel()) this.state.preview();
@@ -339,13 +347,13 @@ class Editor {
   }
 
   /** Read-only view of the running world for tests. */
-  worldSnapshot(): { entities: { objectId: string; x: number; y: number; worldX: number; worldY: number; parent: string; props: Record<string, unknown> }[]; log: string[] } | null {
+  worldSnapshot(): { entities: { objectId: string; assetId: string; name: string; x: number; y: number; worldX: number; worldY: number; parent: string; props: Record<string, unknown> }[]; log: string[] } | null {
     const world = this.world;
     if (!world) return null;
     return {
       entities: world.entities.map((e) => {
         const w = world.worldPosition(e);
-        return { objectId: e.objectId, x: e.x, y: e.y, worldX: w.x, worldY: w.y, parent: e.parent?.objectId ?? '', props: { ...e.props } };
+        return { objectId: e.objectId, assetId: e.assetId, name: e.name, x: e.x, y: e.y, worldX: w.x, worldY: w.y, parent: e.parent?.objectId ?? '', props: { ...e.props } };
       }),
       log: [...world.log],
     };