Hecate refuses any render whose spacing is more than 2 % away from 9.6 µm, and the message says to resample first. Half of the
First Letters eligible volumes (11 of 22: 0175A, 0175B, 0268, 0306B, 0343, 0483A, 0483B, 0490A, 0490B, 0800, 1218) are 8.64 µm,
so on those you either can't run it, or you pass `--spacing-um 9.6` and the model sees letters about 11 % bigger than in training.
This adds an opt-in `--resample` flag: the input stack is rescaled by spacing / 9.6 (linear interpolation) before inference, and
the prediction is mapped back to the input grid so it stays aligned with the segment. Without the flag nothing changes (the error
message now mentions the option). It's refused together with `--output-3d`. `scipy` is added to requirements.txt; it's only
imported when `--resample` is used.
What I measured, on the three PHerc0841 segments with papyrologist labels (official 9.366 µm renders, treated as if they were
8.64 µm scans):
- w00: declared 9.6 without resampling AUC 0.899 → …
