**Replace Flake8 with Ruff, refactor type hints, and enhance archive processing logic**

- Removed `flake8` and `flake8-annotations` from dependencies, replaced by `ruff` for linting.
- Introduced cleaner type hinting and modern Python annotations (PEP 604 style) across multiple modules.
- Moved archive processing to a dedicated helper (`comic.archives`) for improved maintainability.
- Updated and simplified logic for archive file retrieval, directory cleaning, and user access validation.
- Improved error handling and added support for user classification restrictions in API responses.

cbreader/settings/base.py

@@ -247,6 +247,10 @@ SIMPLE_JWT = {
     'ISSUER': 'cbwebreader',
 }
 
+# Renderer formats no longer include a leading dot, so the URL pattern in
+# cbreader/urls.py matches the dot separately. See cbreader/urls.py.
+SWAGGER_USE_COMPAT_RENDERERS = False
+
 FRONTEND_DIR = os.path.join(BASE_DIR, 'frontend')
 
 TEMPLATES = [

cbreader/settings/test.py

@@ -0,0 +1,24 @@
+"""Settings used by the test suite.
+
+In-memory SQLite so the tests do not need a running Postgres, and a scratch comic
+volume that the fixtures fill with generated archives.
+"""
+
+import os
+from pathlib import Path
+
+from cbreader.settings.base import *  # noqa: F403
+from cbreader.settings.base import BASE_DIR
+
+SECRET_KEY = 'test-secret-key'
+ALLOWED_HOSTS = ['*']
+
+DATABASES = {
+    'default': {
+        'ENGINE': 'django.db.backends.sqlite3',
+        'NAME': ':memory:',
+    }
+}
+
+COMIC_BOOK_VOLUME = Path(os.environ.get('COMIC_TEST_VOLUME', BASE_DIR / 'test_comics'))
+MEDIA_ROOT = BASE_DIR / 'test_media'

cbreader/urls.py

@@ -58,7 +58,7 @@ router.register(r'initial_setup', rest.InitialSetup, basename='initial_setup')
 urlpatterns = [
     path('admin/', admin.site.urls),
     path("feed/<user_selector>/", feeds.RecentComicsAPI()),
-    re_path(r'^swagger(?P<format>\.json|\.yaml)$', schema_view.without_ui(cache_timeout=0), name='schema-json'),
+    re_path(r'^swagger\.(?P<format>json|yaml)$', schema_view.without_ui(cache_timeout=0), name='schema-json'),
     re_path(r'^swagger/$', schema_view.with_ui('swagger', cache_timeout=0), name='schema-swagger-ui'),
     re_path(r'^redoc/$', schema_view.with_ui('redoc', cache_timeout=0), name='schema-redoc'),
     path('api/token/', TokenObtainPairView.as_view(), name='token_obtain_pair'),