fix: respond to the SIGTERM signal even when Yazi is in the background and has passed control of the terminal to the spawned process

[sxyazi]

Fixes #796

[musjj]

Thanks for the quick PR! But it looks like that this causes the spawned process to linger after yazi terminates. Some other issues:

After terminating yazi, it kind of messes up my shell in a weird way. In the case of helix, the CPU usage of the lingering process spikes up really badly.

It also causes ^C to not function correctly in the shell, even after the child process is terminated (it normally should create a new empty prompt line).

Maybe a video would be helpful:

yazi_fixed.mp4

But on the other hand, this DOES fix the shutdown problem. For me personally, the only time yazi would be receiving SIGTERM is when my system is shutting down, so I don't really mind it tbh.

[sxyazi]

Thank you for the test. I will create a new PR later to address this issue, which is also related to #726. Let's merge this first.

[sxyazi]

Hi, I made a new PR, please try #812