`identical` returns False after read-write round trip

[martibosch]

Following #26.

The identical method returns False after a read-write round trip following the user guide instructions.

Reproducible example:

import geopandas as gpd
import xarray as xr
import xvec  # noqa: F401

cube = xr.Dataset(
    data_vars={"temperature": [20, 20, 20], "relative_humidity": [60, 60, 60]},
    coords={
        "geometry": gpd.points_from_xy(
            [6.7928, 6.1278, 7.3303], [47.0838, 46.2475, 46.2186]
        )
    },
).xvec.set_geom_indexes("geometry", crs="epsg:4326")

encoded = cube.xvec.encode_cf()
encoded.to_zarr("cube.zarr", mode="w")
roundtripped = xr.open_zarr("cube.zarr").xvec.decode_cf()
print("identical: ", roundtripped.identical(encoded))
print(
    "identical (no geometry): ",
    cube.drop_vars("geometry").identical(roundtripped.drop_vars("geometry")),
)

outputs:

identical:  False
identical (no geometry):  True

also note that I am getting this warning:

/path/to/pixi/env/lib/python3.13/site-packages/zarr/api/asynchronous.py:247: ZarrUserWarning: Consolidated metadata is currently not part in the Zarr format 3 specification. It may not be supported by other zarr implementations and may change in the future.
  warnings.warn(

versions:
geopandas 1.1.2
numpy 2.3.5
xarray 2026.1.0
xvec 0.5.2
zarr 3.1.5