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>

app/api/kill-sandbox/route.ts

@@ -1,7 +1,7 @@
 import { NextResponse } from 'next/server';
 
 declare global {
-  var activeSandbox: any;
+  var activeSandboxProvider: any;
   var sandboxData: any;
   var existingFiles: Set<string>;
 }
@@ -9,19 +9,19 @@ declare global {
 export async function POST() {
   try {
     console.log('[kill-sandbox] Stopping active sandbox...');
-    
+
     let sandboxKilled = false;
-    
+
     // Stop existing sandbox if any
-    if (global.activeSandbox) {
+    if (global.activeSandboxProvider) {
       try {
-        await global.activeSandbox.stop();
+        await global.activeSandboxProvider.terminate();
         sandboxKilled = true;
         console.log('[kill-sandbox] Sandbox stopped successfully');
       } catch (e) {
         console.error('[kill-sandbox] Failed to stop sandbox:', e);
       }
-      global.activeSandbox = null;
+      global.activeSandboxProvider = null;
       global.sandboxData = null;
     }