Add basic linting

ruff.toml

@@ -0,0 +1,7 @@
+[lint]
+# Minimum: syntax errors (E9) + pyflakes (F = undefined names, unused imports, etc.)
+select = ["E9", "F"]
+
+[lint.per-file-ignores]
+# Tests commonly import for side-effects and use intentional bare assignments
+"doajtest/**" = ["F401", "F841"]

setup.py

@@ -74,6 +74,7 @@
                  "bs4==0.0.2",   # beautifulsoup for HTML parsing
                  'openapi-spec-validator~=0.5',
                  "cryptography~=42.0", # for ad-hoc https
+                 "ruff",
                  ],
 
         # additional test dependencies for the test-extras target