Save current v2 sandbox implementation before styling refactor

- Modified sandbox API routes for v2 implementation
- Updated sandbox providers (E2B and Vercel)
- Added styling-reference directory with Firecrawl AI-ready website
- Preparing for styling system port from Firecrawl design

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

lib/sandbox/providers/vercel-provider.ts

@@ -450,6 +450,10 @@ body {
     return this.sandboxInfo?.url || null;
   }
 
+  getSandboxInfo(): SandboxInfo | null {
+    return this.sandboxInfo;
+  }
+
   async terminate(): Promise<void> {
     if (this.sandbox) {
       console.log('[VercelProvider] Terminating sandbox...');