{
  "free_before": 2665308160,
  "unique_input_bytes": 2182682276,
  "minimum_remaining_bytes": 1073741824,
  "strategy": "Guarded compressed writer checks free space every 1 MiB; no uncompressed staging; source remains intact on failure",
  "source_removal_requires": "Complete actual cloud readback and all source/member hashes match"
}