Add API_TIMEOUT_MS configuration option

- Add API_TIMEOUT_MS to config.example.json with default value of 600000ms
- Update README.md and README_zh.md to document the new configuration option
- Modify codeCommand.ts to use the configured timeout value instead of hardcoded 600000ms
- Default to 10 minutes (600000ms) if not set in config

config.example.json

@@ -113,5 +113,6 @@
     "webSearch": "gemini,gemini-2.5-flash"
   },
   "APIKEY": "your-secret-key",
-  "HOST": "0.0.0.0"
+  "HOST": "0.0.0.0",
+  "API_TIMEOUT_MS": 600000
 }