[Feat]: Removing agents

### Is your feature request related to a problem? Please describe.

Working with A2A It seems to be very incontinent that I can't remove agents in the GUI without restating the program, or disabling agents for particular chats.

### Describe the solution you'd like

Removing or disabling agents

### Describe alternatives you've considered

_No response_

### Additional context

Might require to be conversation specific (considering the sysprompt)

### Code of Conduct

- [x] I agree to follow this project's Code of Conduct