- Accept source=auto in the version download route (was 400 Bad Request),
so bulk/project downloads of Bunny videos no longer fail.
- Bulk/project downloads now request the original (uncompressed) Bunny file
so quality never drops (was source=auto which could fall back to compressed).
- Project/selected downloads default to the latest version of each video and
add a separate "All versions" option in the download dropdowns.