Defensive access guards against download_single returning ok=True
without title/artist keys, avoiding a KeyError in the job worker.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Live end-to-end test surfaced two bugs in youtube tagging:
- `--replace-in-metadata artist .* NAME` matched twice and doubled the
artist tag (e.g. "SLVMLORDSLVMLORD"). Anchor with ^.*$ to match once.
- Use only the first artist when several are present (SLVMLORD, not
"SLVMLORD, Travis Bradley, ...") for both the embedded tag and the
spoken/echoed API messages.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>