Add support for HPA behavior configuration to control scaling stabilization in Langgraph helm charts

**Problem:**
Currently, the HPA template in both api-server and queue doesn't support configuring the behavior field, which is essential for controlling scaling stabilization windows and policies. This causes rapid scaling up and down (thrashing) in production environments, especially for applications with long-running tasks with 5-10 minute graph executions.
Without behavior configuration, HPA scales too aggressively:

- Scales down immediately when metrics drop, potentially interrupting long-running tasks
- Causes unnecessary pod churn and instability
- Increases costs due to frequent scaling operations
- Creates poor user experience with connection drops

Inspect the HPA templates for both the api-server and queue charts, then identify how their configuration is currently exposed. Add support for the Kubernetes HPA behavior field so scaling stabilization and policies can be configured, and verify that both charts render the requested behavior configuration.

Written by the indexing model from the issue text.