Layer to offset file freezes up with large layer

[mhairifin]

When the layer is sufficiently large, the code to apply the layer freezes up running locally in WSL. This is presumably as it is loading the whole layer and the csv at the same time, and this is a large amount of data in memory.

Example data here (with files in example data store): https://imperiallondon.sharepoint.com/:f:/r/sites/IMAPOps-PH/Shared%20Documents/Data%20Processing/Calibration/ExampleBug?csf=1&web=1&e=Z7M8ya as data was too large to upload to github

Running command:

imap-mag calibration apply --layers imap_mag_manual-layer_20250930_v001.json --from 2025-09-30 imap_mag_l1b_burst-mago_20250930_v002.cdf