Fix Deno timeout type compatibility

- Change timeoutId type from NodeJS.Timeout to number | NodeJS.Timeout
- This allows compatibility with both Deno (returns number) and Node.js (returns NodeJS.Timeout)
- Fixes Deno compilation error in release workflow

🤖 Generated with [Claude Code](https://claude.ai/code)

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

Author: baryhuang

backend/handlers/chat.ts

@@ -75,7 +75,7 @@ async function* executeAgentHttpRequest(
     const decoder = new TextDecoder();
 
     try {
-      let timeoutId: NodeJS.Timeout | null = null;
+      let timeoutId: number | NodeJS.Timeout | null = null;
 
       while (true) {
         // Add timeout for each read operation