After gallery-dl returns, parse stdout for written file paths and run
the magic-byte validator on each. Files that fail are moved to
{download_path}/_quarantine/{subscription}/{platform}/ with a sidecar
JSON capturing the source URL, validation reason, and original path —
enough for an operator to redownload-from-source or delete.
Adds ErrorType.VALIDATION_FAILED. A successful gallery-dl run that
produced quarantined files is now a soft failure (success=False,
error_message names the dominant failure reason and count) so the
source's error_count ticks up and the dashboard surfaces it. Gated
by download.validate_files setting (default True).
files_quarantined and quarantined_paths are persisted into download
metadata for the UI/API to consume.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
bvandeusen
2765c464bd