Enable pre-commit & add workflow hook

Author: acdha

.github/workflows/pre-commit.yml

@@ -0,0 +1,30 @@
+name: unit tests
+
+permissions:
+  contents: write
+
+on:
+  push: # run on every push or PR to any branch
+  pull_request:
+
+jobs:
+  pre-commit:
+    name: pre-commit
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Setup Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: "3.13"
+
+      - run: pip install pre-commit
+
+      - uses: actions/cache@v4
+        with:
+          path: ~/.cache/pre-commit
+          key: pre-commit|${{ hashFiles('.pre-commit-config.yaml') }}
+
+      - run: pre-commit run --show-diff-on-failure --color=always

.pre-commit-config.yaml

@@ -0,0 +1,45 @@
+exclude: ".*/vendor/.*"
+repos:
+  - repo: https://github.com/pre-commit/pre-commit-hooks
+    rev: v5.0.0
+    hooks:
+      - id: check-added-large-files
+        args: ["--maxkb=128"]
+      - id: check-ast
+      - id: check-byte-order-marker
+      - id: check-case-conflict
+      - id: check-docstring-first
+      - id: check-executables-have-shebangs
+      - id: check-json
+      - id: check-merge-conflict
+      - id: check-symlinks
+      - id: check-toml
+      - id: check-xml
+      - id: check-yaml
+      - id: debug-statements
+      - id: detect-private-key
+      - id: end-of-file-fixer
+      - id: mixed-line-ending
+        args: ["--fix=lf"]
+      - id: pretty-format-json
+        args: ["--autofix", "--no-sort-keys", "--indent=4"]
+      - id: trailing-whitespace
+
+  - repo: https://github.com/executablebooks/mdformat
+    rev: 0.7.22
+    hooks:
+      - id: mdformat
+        additional_dependencies:
+          - mdformat-gfm
+
+  - repo: https://github.com/gruntwork-io/pre-commit
+    rev: v0.1.29
+    hooks:
+      - id: shellcheck
+
+  - repo: https://github.com/astral-sh/ruff-pre-commit
+    rev: v0.11.10
+    hooks:
+      - id: ruff-check
+        args: ["--fix", "--exit-non-zero-on-fix"]
+      - id: ruff-format