Add v2 sandbox implementation with new API routes and sandbox library

lib/sandbox/factory.ts

@@ -0,0 +1,42 @@
+import { SandboxProvider, SandboxProviderConfig } from './types';
+import { E2BProvider } from './providers/e2b-provider';
+import { VercelProvider } from './providers/vercel-provider';
+
+export class SandboxFactory {
+  static create(provider?: string, config?: SandboxProviderConfig): SandboxProvider {
+    // Use environment variable if provider not specified
+    const selectedProvider = provider || process.env.SANDBOX_PROVIDER || 'e2b';
+    
+    console.log(`[SandboxFactory] Creating ${selectedProvider} provider`);
+    
+    switch (selectedProvider.toLowerCase()) {
+      case 'e2b':
+        return new E2BProvider(config || {});
+      
+      case 'vercel':
+        return new VercelProvider(config || {});
+      
+      default:
+        throw new Error(`Unknown sandbox provider: ${selectedProvider}. Supported providers: e2b, vercel`);
+    }
+  }
+  
+  static getAvailableProviders(): string[] {
+    return ['e2b', 'vercel'];
+  }
+  
+  static isProviderAvailable(provider: string): boolean {
+    switch (provider.toLowerCase()) {
+      case 'e2b':
+        return !!process.env.E2B_API_KEY;
+      
+      case 'vercel':
+        // Vercel can use OIDC (automatic) or PAT
+        return !!process.env.VERCEL_OIDC_TOKEN || 
+               (!!process.env.VERCEL_TOKEN && !!process.env.VERCEL_TEAM_ID && !!process.env.VERCEL_PROJECT_ID);
+      
+      default:
+        return false;
+    }
+  }
+}