Request: Promote Peak EWMA load balancing policy from contrib to core

## Context

I'm interested in understanding the process and criteria for promoting extensions from `contrib` to `core` in Envoy.

Specifically, I'm looking at the Peak EWMA load balancing policy (#40653), which is currently in contrib. I believe this extension would be valuable as a core feature, but I'd like to understand what steps or criteria are needed for such a promotion.

## Questions

1. What are the general requirements for a contrib extension to be considered for core?
2. Are there specific metrics or adoption thresholds that need to be met?
3. What is the process for proposing or requesting this promotion?
4. Are there any particular concerns or improvements needed for the Peak EWMA policy specifically?

## Related

- PR: https://github.com/envoyproxy/envoy/pull/40653

I'd appreciate any guidance from the maintainers on how we can work towards getting valuable contrib extensions like this into core.

Thanks!