Port to the plain-string trait profiles from mlwp-data-specs#42 #51

Problem

mlwp-tools/mlwp-data-specs#42 replaced the Space, Time and Uncertainty enums with classes whose members are plain strings. Time.FORECAST is now the str "forecast". The classes can't be called, and their members have no .value, so mxalign fails wherever it does either.

The failures come from Time() takes no arguments, Space() takes no arguments and 'str' object has no attribute 'value'.

CI doesn't show this because [tool.uv.sources] pins mlwp-data-specs to 059f382. It appears in a dev environment with a local mlwp-data-specs checkout on main, and it will appear at the next pin bump.

main is affected too, but less: its 3 tests pass because they don't reach update_*_trait, which still calls new_trait.value.

What needs changing

On refactor/alignment:

On main, the traits.py lines are 24, 30 and 36.

Space(value) and Time(value) also raised ValueError on an unknown value, so the accessors need an explicit check to keep that, for example:

value = self._trait(TIME_TRAIT_ATTR)
if value not in Time:
    raise ValueError(f"Invalid '{TIME_TRAIT_ATTR}' attribute: {value!r}")
return value

The _space and _time return annotations and docstrings become str.

Notes

• Bump the mlwp-data-specs pin in the same change. Without .value, the current pin would write enum members into the attributes.
• feat/ensemble-alignment (feat: ensemble-aware alignment (uncertainty predicates, NaN broadcasting, Delaunay member dims) #45) hasn't been checked.
• CI: test downstream packages and enforce version bumps for breaking changes mlwp-data-specs#41 proposes running downstream tests on mlwp-data-specs PRs, which would catch this kind of break before it merges.