Add ruff config and document Postgres test run

- Lint rules (pycodestyle, pyflakes, bugbear, isort, pyupgrade, bandit)
  in pyproject.toml; ruff pinned in requirements-dev
- Full suite verified against PostgreSQL (embedded pgserver), plus a
  production-like check: collectstatic with manifest storage, fresh
  migrations, ensure_admin and all main pages with DEBUG off

Co-Authored-By: Claude Opus 5.5 <[email protected]>

CLAUDE.md

@@ -53,6 +53,10 @@ no JS build step: plain forms with small progressive enhancements in `static/js/
 ```bash
 # Local (Windows dev box: venv lives at C:\Users\kyled\.venvs\kochbuch due to path-length issues)
 python -m pytest                                  # tests (SQLite)
+python -m ruff check .                            # lint (config in pyproject.toml)
+# Postgres without Docker (dev box): pip install pgserver; start it, then
+# POSTGRES_HOST=127.0.0.1 POSTGRES_PORT=<port> POSTGRES_USER=postgres POSTGRES_DB=postgres python -m pytest
+# (the Windows pgserver build lacks tz data: copy tzdata/zoneinfo to pginstall/share/postgresql/timezone)
 python scripts/dev_server.py                      # http://localhost:8000, [email protected]
 SECRET_KEY=dev python manage.py makemigrations
 

pyproject.toml

@@ -7,3 +7,15 @@ requires-python = ">=3.12"
 DJANGO_SETTINGS_MODULE = "config.settings_test"
 testpaths = ["tests"]
 addopts = "-q"
+
+[tool.ruff]
+line-length = 120
+extend-exclude = ["*/migrations/*"]
+
+[tool.ruff.lint]
+select = ["E", "F", "W", "B", "I", "UP", "S"]
+ignore = ["E501", "S311"]
+
+[tool.ruff.lint.per-file-ignores]
+"tests/*" = ["S101", "S104", "S105", "S106"]
+"recipes/schema_org.py" = ["S110"]  # malformed third-party HTML must never break an import

requirements-dev.txt

@@ -1,3 +1,4 @@
 -r requirements.txt
 pytest==9.2.0
 pytest-django==4.14.0
+ruff==0.17.3