Show component-indicator selection badge in the canvas

.component-indicator existed in editor.css but was never rendered
anywhere. Add RenderNode.tsx as a Craft.js <Editor onRender> override
and wire it in App.tsx: for the currently-selected node (excluding
ROOT) it portals a floating badge showing the node's displayName plus
a "select parent" chevron wired to actions.selectNode(parentId). Every
other node's render passes through untouched (a Fragment, no extra
DOM), and the badge portals to document.body positioned via
getBoundingClientRect rather than wrapping nodes in extra DOM, so it
can't perturb canvas layout and never appears in toHtml export.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

craft/src/App.tsx

@@ -1,6 +1,7 @@
 import React from 'react';
 import { Editor } from '@craftjs/core';
 import { EditorShell } from './editor/EditorShell';
+import { RenderNode } from './editor/RenderNode';
 import { componentResolver } from './components/resolver';
 import { WhpConfig } from './types';
 import { EditorConfigProvider } from './state/EditorConfigContext';
@@ -23,7 +24,7 @@ export const App: React.FC<AppProps> = ({ whpConfig }) => {
   return (
     <EditorConfigProvider config={whpConfig}>
       <SiteDesignProvider>
-        <Editor resolver={componentResolver} enabled={true}>
+        <Editor resolver={componentResolver} enabled={true} onRender={RenderNode}>
           <PageProvider>
             <SitesmithProvider>
               <EditorShell />