Remove validate-pyproject pre-commit hook (#337)

The validate-pyproject hook with the validate-pyproject-schema-store[all]
plugin depends on daily automated releases from JSON Schema Store. A broken
tox schema reference in the latest release caused a spurious CI failure
(KeyError: 'https://json.schemastore.org/tox.json'), even though this project
doesn't use tox -- the [all] extra loads schemas for every tool on SchemaStore.

This is the same class of breakage that has occurred before upstream
(henryiii/validate-pyproject-schema-store#9), making the hook inherently
brittle. The value it provides is low since configuration errors in tool
sections (ruff, mypy, pytest, etc.) are already caught when those tools run,
and build metadata errors are caught by the build system itself.

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

Author: 2 people

.pre-commit-config.yaml

@@ -76,12 +76,6 @@ repos:
         entry: PyBind|Numpy|Cmake|CCache|Github|PyTest
         exclude: .pre-commit-config.yaml
 
-  - repo: https://github.com/abravalheri/validate-pyproject
-    rev: "v0.16"
-    hooks:
-      - id: validate-pyproject
-        additional_dependencies: ["validate-pyproject-schema-store[all]"]
-
   - repo: https://github.com/python-jsonschema/check-jsonschema
     rev: "0.28.2"
     hooks: