Editor offset, global On click, Coin container in the jump-and-run seed

- SceneObject.editorOffset (x/y): shifts only where an object is drawn in
  the Scene tab, cascades to children, undo-able with a reset action.
  Never written into container templates.
- On click without an owner now fires for any click inside the camera
  frame instead of hit-testing the (editor-only) behavior symbol.
- seed-jumprun: coins are a "Coin" container (sprite + trigger), nested
  containers are expanded recursively, Destroy targets the coin's parent,
  and the clock uses a Ceil node instead of ToText.

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

src/core/graph/nodes.ts

@@ -42,7 +42,7 @@ registerNode({
   type: 'OnClick',
   label: 'On click',
   category: 'event',
-  description: 'Runs when the mouse is pressed on the owner (or on anything parented below it) in the Game tab.',
+  description: 'Runs when the mouse is pressed on the owner (or on anything parented below it) in the Game tab. Without an owner it runs on a click anywhere in the game view.',
   inputs: [],
   outputs: [exec(), num('x', 'world x'), num('y', 'world y')],
   params: [],