Preserve HDU headers in spherex_cutouts.md notebook #238
Description
In the MEF output produced by the spherex_cutouts.md notebook, we should be preserving the headers that came from IBE as much as possible. Currently, VERSION is missing from HDU 0 header. Need to check the other HDUs as well. Can the notebook be updated to preserve what's currently missing? For comparison, here is a link to run the ibe cutout service without the notebook: https://irsa.ipac.caltech.edu/ibe/data/spherex/qr2/level2/2025W19_2B/l2b-v20-2025-247/2/level2_2025W19_2B_0346_1D2_spx_l2b-v20-2025-247.fits?center=210.80227,54.34895d&size=0.1