/agent & /model should auto complete the avialable agents/models #1634
Description
Describe the feature or problem you'd like to solve
right now I run the command with a random invalid value to force copilot to list the available values, would be nice to have auto complete so I don't have to first get the list and then copy a specific one
Proposed solution
No response
Example prompts or workflows
No response
Additional context
No response