Context

Claude has been struggling with a few things due to our AGENTS.md:

• It tries to use hatch, since it is called out
• It tries to run the synchro script directly instead of using a justfile target, meaning it can use the wrong version of ruff
• It often tries to make direct changes to synchronous files

We should remove mentions of hatch, only mention synchro using a justfile target, and clarify which files should NOT be edited directly by Claude, such as the files in test/ that also exist in test/asynchronous.
We might also consider telling the bot to manually run just syncho (new target) prior to running a test command or commiting.

Definition of done

AGENTS.md is updated and has been tested a few times to see if the patterns work better.

Pitfalls

Adding too much text to the file can be counterproductive. We should be as terse as possible.