Get Upload

Persisted upload state for one recording.

Fields are required (no defaults) so JSON written by older versions surfaces as a parse error instead of silently defaulting to zero values.

destination and key are destination-agnostic: for the S3 destination they map to bucket name and object key; future destinations (GCS / local server) fill in equivalents (bucket + object name, host + path). etag is the destination's result identifier (S3 ETag, GCS generation, local hash) and is None when the destination does not return one.