Fix circular import in ACP agent/message modules blocking direct ACP Agent import

[pauleveritt]

Hey Will, thanks for Toad, I'm wiring it up as the front-end for another crack at my weird agent ideas.

I'm working from main and ran into a circular import. When importing Toad's ACP agent directly, the import currently fails with a circular import:

ImportError: cannot import name 'Mode' from partially initialized module 'toad.acp.agent'

The cycle is:

• toad.acp.agent imports toad.acp.messages
• toad.acp.messages imports Mode from toad.acp.agent
• Mode has not been defined yet when messages is imported

[willmcgugan]

Hi Paul. I think some of the imports of Mode should be moved inside a if TYPE_CHECKING block. I'll put that on my list.

[willmcgugan]

Should be fixed now. But note that I never really intended Toad to be treated as a library.

Something that may impact you. I've pinned dependancies. With the recent supply chain attacks, this seems to be safest approach. And it prevents a bug in a dependency from breaking Toad.

[pauleveritt]

@willmcgugan My imports are mostly about confirming behavior, I should have mentioned that it was a lower-than-low priority. Thanks for super-fast response all the same.