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/.gitignore

@@ -0,0 +1,6 @@
+node_modules/
+dist/
+.playwright-mcp/
+test-results/
+playwright-report/
+*.tsbuildinfo