Network Path (UNC) Support and Resilience

As a system administrator, I want to configure network paths in UNC format (e.g., \Server\Share) for my sources and targets, So that I can reliably back up data to or from remote servers, NAS, and network shares.

Given a valid UNC path for the target directory,
When the backup is launched,
Then the engine successfully accesses the network location and writes the files there.

Given an active file transfer to a network drive,
When the network connection is suddenly lost,
Then the engine intercepts the error, logs the failure via the logging DLL, and cleanly interrupts the transfer without causing a general application crash.

Given a file is transferring to a UNC target,
When the network connection drops mid-transfer,
Then the engine catches the error, logs it, attempts to delete the incomplete partial file from the target directory, and if the deletion itself fails, logs a second CLEANUP_FAILED event with the corrupted file path.