fix: reduce maxDuration to 60s for Vercel Hobby plan compatibility

Routes with maxDuration=300 were silently failing on Vercel's edge
routing layer - requests never reached the serverless function (no
logs appeared). Vercel Hobby plan has a 60s max function duration.

Affected routes:
- /api/agents/[id]/conversation/[conversationId]
- /api/agents/[username]/[uid]/conversation/[conversationId]
- /api/mcp/[username]/[slug]/[transport]

The issue caused these routes to hang indefinitely until client timeout.

templates/vercel-executor/app/api/execute-tool/route.ts

@@ -88,17 +88,9 @@ export async function POST(req: NextRequest): Promise<NextResponse<ExecuteToolRe
       });
     }
 
-    // 2) Build environment setup for the script
-    const envSetup = env
-      ? Object.entries(env)
-          .map(([key, value]) => `process.env[${JSON.stringify(key)}] = ${JSON.stringify(value)};`)
-          .join('\n')
-      : '';
-
-    // 3) Write the execution script (CommonJS for require())
+    // 2) Write the execution script (CommonJS for require())
+    // Note: env vars are passed via runCommand's env option, not embedded in script
     const script = `
-${envSetup}
-
 (async () => {
   try {
     const pkg = require(${JSON.stringify(packageName)});