New Agents default to Private organization access

When you create a new Agent in NinjaCat, its Organization Access now defaults to Private instead of Can Edit. New agents stay visible only to you until you choose to share them — useful while you're still experimenting or iterating. When the agent is ready, you can change Organization Access to Can Edit (or another level) from the agent's permissions settings.

This change applies only to newly created agents. Existing agents keep whatever Organization Access they already have — nothing is changed retroactively.