fix: duplicate search no longer hangs on files swapped for FIFOs
Candidates were reopened by path with os.Open after the scan. A file
replaced by a FIFO (or a symlink to one) blocked open(2) forever, and
context cancellation could not interrupt it, wedging the duplicate view
and --duplicates. Content is now opened with O_NOFOLLOW|O_NONBLOCK on
Unix; the existing regular-file check then skips it.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Andy DixonandClaude Opus 5.5