Fix
Age-restricted video downloads work again
We fixed cookie sync so downloads that require signed-in access, including 18+ or sensitive videos, can complete when the source platform allows access.
- Cookie export now checks for a valid cookie file instead of trusting yt-dlp's non-zero exit code.
- Synced browser cookies are preserved safely, so a failed export no longer overwrites the last working cookie jar.
- Downloads that need an authenticated session, including age-restricted or sensitive content, no longer fail just because cookies were missing.
- We also blocked same-tick duplicate submissions that could create duplicate download records.