`derive_label` doesn't respect non-integer naming of levels

[imagejan]

I can create an OME-Zarr container with named scale levels, e.g.:

create_empty_ome_zarr(
  store=...,
  shape=...,
  xy_pixelsize=...,
  levels=["s0", "s1"],
)

.. but when I derive a label from it with derive_label, the levels are always named ["0", "1"] and there's no option to get named levels.

I would expect the levels of the new label to be the same as in the parent image by default (possibly with an option to override the default behavior).

---

It seems the levels of the new Label are set here:

ngio/src/ngio/images/_label.py

Line 321 in 59d759a

levels=ref_meta.levels,

.. where the levels is defined as int, not as Sequence[str]:

ngio/src/ngio/images/_image.py

Lines 409 to 412 in 59d759a

	@property
	def levels(self) -> int:
	"""Return the number of levels in the image."""
	return self._meta_handler.meta.levels

[lorenzocerrone]

Thanks for spotting it, @imagejan. Indeed, I was only deriving based on the number of pyramid levels, but using the actual path would be better. I will fix it with a quick patch