Failure during file file copy is ignored

Description

If a failure is encountered during the final copy step in post-processing here: https://github.com/Unmanic/unmanic/blob/master/unmanic/libs/postprocessor.py#L306, the job will appear to complete successfully in the UI, because the inner exception is caught and returned as a bool, but this call site doesn't check the result.

The result is that the job appears to succeed, but didnt!

Steps to Reproduce

I'm running unmanic in docker. My /library is an nfs mount, and i initially didn't set a volume bind for /tmp/unmanic.

This was yielding the following error on the aforementioned call site.

OSError: [Errno 18] Invalid cross-device link: '/tmp/unmanic/unmanic_file_conversion-geltd-1713877537/movie-ynnzb-1713957463.mkv' -> '/library/movie.mkv.unmanic.part'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/local/lib/python3.10/dist-packages/unmanic/libs/postprocessor.py", line 360, in __copy_file
    shutil.move(file_in, part_file_out, copy_function=shutil.copyfile)
  File "/usr/lib/python3.10/shutil.py", line 836, in move
    copy_function(src, real_dst)
  File "/usr/lib/python3.10/shutil.py", line 256, in copyfile
    with open(dst, 'wb') as fdst:
PermissionError: [Errno 13] Permission denied:

The error itself, i think it's a me, problem. It's the fact that I thought it was working correctly that's the bug here, to me.

Expected behavior: The UI should show that the job failed (and ideally why, the traceback)

Actual behaviour: it appears to succeed. Reproduces how often: 100%

Versions

The offending line is as described on master.

Installation Method Used

Docker

I'm experiencing the same "bug" triggered by a different method (library is an rclone mount). Also running unmanic as a Docker container.

Traceback (most recent call last):
  File "/usr/lib/python3.10/shutil.py", line 816, in move
    os.rename(src, real_dst)
OSError: [Errno 18] Invalid cross-device link: '/tmp/unmanic/unmanic_file_conversion-jltpr-1715075521/movie-jdbmv-1715077579.mkv' -> '/library/Movies/movie.mkv.unmanic.part'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/local/lib/python3.10/dist-packages/unmanic/libs/postprocessor.py", line 360, in __copy_file
    shutil.move(file_in, part_file_out, copy_function=shutil.copyfile)
  File "/usr/lib/python3.10/shutil.py", line 836, in move
    copy_function(src, real_dst)
  File "/usr/lib/python3.10/shutil.py", line 267, in copyfile
    _fastcopy_sendfile(fsrc, fdst)
  File "/usr/lib/python3.10/shutil.py", line 162, in _fastcopy_sendfile
    raise err
  File "/usr/lib/python3.10/shutil.py", line 142, in _fastcopy_sendfile
    sent = os.sendfile(outfd, infd, offset, blocksize)
OSError: [Errno 9] Bad file descriptor: '/tmp/unmanic/unmanic_file_conversion-jltpr-1715075521/movie-jdbmv-1715077579.mkv' -> '/library/Movies/movie.mkv.unmanic.part'

Unmanic / unmanic