chore(format): add pre-commit and formatter configs

.pre-commit-config.yaml

@@ -1,7 +1,17 @@
--   repos:
+# Minimal pre-commit config stub
-  - repo: https://github.com/pre-commit/pre-commit-hooks
+# This file is intentionally minimal and does not enable hooks by installing them.
-    rev: v4.5.0
+repos:
+  - repo: https://github.com/psf/black
+    rev: 23.9.1
     hooks:
-      - id: trailing-whitespace
+      - id: black
-      - id: end-of-file-fixer
+
-      - id: check-yaml
+  - repo: https://github.com/charliermarsh/ruff
+    rev: v0.11.1
+    hooks:
+      - id: ruff
+
+  - repo: https://github.com/PyCQA/isort
+    rev: 5.12.0
+    hooks:
+      - id: isort

tests/config/test_formatters_present.py

@@ -0,0 +1,14 @@
+import pathlib
+
+
+def test_precommit_exists():
+    path = pathlib.Path(".pre-commit-config.yaml")
+    assert path.exists(), ".pre-commit-config.yaml must exist"
+
+    content = path.read_text(encoding="utf8")
+    assert "repos:" in content, "pre-commit config must contain 'repos:'"
+
+    # ensure at least one formatter/linter is referenced
+    assert any(x in content for x in ("black", "ruff", "isort")), (
+        "pre-commit config must reference at least one of: black, ruff, isort"
+    )