Add Craft.js site builder (v2) - complete rebuild from GrapesJS

Rebuilt the visual site builder from scratch using Craft.js, React 18,
and TypeScript. The new editor renders directly in the DOM (no iframe),
supports 40+ components, multi-page with shared header/footer, 16
templates, full-spectrum color/gradient controls, custom head code
injection, save/publish workflow, and auto-save.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

craft/src/state/EditorConfigContext.tsx

@@ -0,0 +1,22 @@
+import React, { createContext, useContext, ReactNode } from 'react';
+import { WhpConfig } from '../types';
+
+interface EditorConfigContextValue {
+  whpConfig: WhpConfig | null;
+  isWHP: boolean;
+}
+
+const EditorConfigContext = createContext<EditorConfigContextValue>({
+  whpConfig: null,
+  isWHP: false,
+});
+
+export const useEditorConfig = () => useContext(EditorConfigContext);
+
+export const EditorConfigProvider: React.FC<{ config: WhpConfig | null; children: ReactNode }> = ({ config, children }) => {
+  return (
+    <EditorConfigContext.Provider value={{ whpConfig: config, isWHP: !!config }}>
+      {children}
+    </EditorConfigContext.Provider>
+  );
+};