[bug] Agent slugs default to `new-agent` and can't be edited

[ashrafchowdury]

Agents created from the home page or onboarding flow get slugs that always start with new-agent, and the slug does not appear to be editable.

This looks harmless at first, but it will become harder to manage as more agents are created because many slugs will look very similar.

The issue is observed for agents created from:

• the home page
• the onboarding flow

[linear-code]

AGE-3971