Fix RTD build: drop -W flag from sphinx docs:build

The old RTD config had fail_on_warning: false. Upstream libraries
(xarray, geopandas) emit harmless import warnings that -W promotes
to fatal errors. Remove -W to match previous behavior.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: timtreis

pyproject.toml

@@ -82,7 +82,7 @@ dependency-groups = [ "dev" ]
 dependency-groups = [ "doc" ]
 
 [tool.hatch.envs.docs.scripts]
-build = "sphinx-build -M html docs docs/_build -W {args}"
+build = "sphinx-build -M html docs docs/_build {args}"
 open = "python -m webbrowser -t docs/_build/html/index.html"
 clean = "git clean -fdX -- {args:docs}"