Serverless Changelog, 08/09/2025

### Description

Create the serverless changelog for the week of September 8

### Resources

-

### Which documentation set does this change impact?

Elastic Cloud Serverless only

### Feature differences

-

### What release is this request related to?

N/A

### Serverless release

-

### Collaboration model

The documentation team

### Point of contact.

**Main contact:** @

**Stakeholders:**
