This PR also adds items within the "Add Agent" menu to:
1. Add more agent servers from extensions, opening up the extensions
page with "Agent Servers" already filtered
2. Go to the agent server + ACP docs to learn more about them
I feel like having them there is a nice way to promote this knowledge
from within the product and have users learn more about them.
<img width="500" height="540" alt="Screenshot 2025-11-11 at 10 46 3@2x"
src="https://github.com/user-attachments/assets/9449df2e-1568-44d8-83ca-87cbb9eefdd2"
/>
Release Notes:
- agent: Enabled uninstalled agent servers from the agent panel's
settings view.