reduce watchdog interval to 5s

[ByronHsu]

Motivation

The current watchdog interval is 60s, which is a bit too long. Say if i want to gracefully terminate a idle sglang server by sending a TERM signal, it needs to wait around ~60s to take effect.

Modifications

This PR reduces the interval to 5s

Checklist

• Format your code according to the Contributor Guide.
• Add unit tests as outlined in the Contributor Guide.
• Update documentation as needed, including docstrings or example tutorials.

[ByronHsu]

@merrymercy let me know if you have any concerns