Datasets:
Add SETA cached Apptainer environments
Adds ten pristine Apptainer environment bundles under the SETA baseline folder. Each environment passed stage 3 on a representative task. References cover all 3,126 tasks by exact environment-content hash. This does not claim fresh functional validation of all tasks. Task payloads remain unchanged. The following commit adds pinned automatic-download metadata and checksums.
Verification: all ten uploaded bundles were freshly downloaded, checksum-verified, inspected as SIF images, and reused as cache hits without rebuilding. All 3,126 task references are present and task payloads are unchanged.
Loader compatibility: this dataset-scoped cached_images/ layout requires the accompanying change to validation/publishing/image_release.py in the local OT_next_data checkout. That source change has not been pushed to GitHub. The local loader tests pass (11 tests).