fix: threading applications using ape

[Gonmeso]

What I did

Add signal handling for applications that use Ape using threads, this could be APIs, streamlit applications and prefect flows

fixes: #1164

How I did it

Checked if we are running in the main thread or not, if we are signaling is applied as usual, otherwise it won't be applied. This means more traceback for threaded applications but it will work.

How to verify it

Previously ape fails at import time due to signalling failing to be achieved on a child thread.

Running the following script without the change will result in an error ValueError: signal only works in main thread of the main interpreter :

import threading

def import_ape():
    import ape

thread = threading.Thread(target=import_ape)

thread.start()
thread.join()

print("Done")

Once the change is applied ape is successfully loaded

Checklist

• All changes are completed
• New test cases have been added
• Documentation has been updated