Add CLAUDE.md, pre-commit config, and pyproject.toml

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

.pre-commit-config.yaml

@@ -0,0 +1,11 @@
+repos:
+  - repo: https://github.com/pre-commit/pre-commit-hooks
+    rev: v5.0.0
+    hooks:
+      - id: trailing-whitespace
+      - id: end-of-file-fixer
+      - id: check-yaml
+        args: ['--allow-multiple-documents']
+      - id: check-json
+      - id: check-merge-conflict
+      - id: check-added-large-files