Organizing a completed download deleted its done entry, losing the
original video URL. Now a hidden sidecar '.<filename>.metube.json' is
written next to the video at organize time with url/title/uploader/
website/downloaded_at. /library/files attaches it as 'meta', library
delete removes it, and the library browser shows an external-link icon
opening the original page for files that have it. No backfill for
previously organized files.
Also records the published 1.18 image in DEPLOY.md.
tigerenwork