remove pyspark dependency and wikiq_spark packaging references

The spark indexing pass is moving out of this repository, and
src/wikiq_spark was never committed here: pyproject.toml declared a
wikiq-spark console script and wheel package that do not exist in the
tree, and pulled in pyspark for every install of a tool that never
imports it. The --print-schema flag and its Spark-format schema
converters remain, since they are pure Python and produce the schema
the external indexing pass consumes.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
(cherry picked from commit 392211af17)

pyproject.toml

@@ -14,7 +14,6 @@ dependencies = [
     "mwtypes>=0.4.0",
     "mwxml>=0.3.6",
     "pyarrow>=20.0.0",
-    "pyspark>=3.5.0",
     "pywikidiff2",
     "sortedcontainers>=2.4.0",
     "yamlconf>=0.2.6",
@@ -22,14 +21,13 @@ dependencies = [
 
 [project.scripts]
 wikiq = "wikiq:main"
-wikiq-spark = "wikiq_spark:main"
 
 [build-system]
 requires = ["hatchling"]
 build-backend = "hatchling.build"
 
 [tool.hatch.build.targets.wheel]
-packages = ["src/wikiq", "src/wikiq_spark"]
+packages = ["src/wikiq"]
 
 [tool.uv.sources]