Refactor test utilities and enhance ASGI settings

- Cleaned up and standardized assertions in ApiTestMixin for API response validation.
- Updated ASGI settings to use os.environ for setting the DJANGO_SETTINGS_MODULE.
- Removed unused imports and improved formatting in settings.py.
- Refactored URL patterns in urls.py for better readability and organization.
- Enhanced view functions in views.py for consistency and clarity.
- Added .flake8 configuration for linting and style enforcement.
- Introduced type stubs for django-environ to improve type checking with Pylance.

media/urls.py

@@ -8,6 +8,14 @@ urlpatterns = [
     path(
         "upload/<int:photo_id>/", views.delete_photo, name="delete"
     ),  # Updated to match frontend
-    path("upload/<int:photo_id>/primary/", views.set_primary_photo, name="set_primary"),
-    path("upload/<int:photo_id>/caption/", views.update_caption, name="update_caption"),
+    path(
+        "upload/<int:photo_id>/primary/",
+        views.set_primary_photo,
+        name="set_primary",
+    ),
+    path(
+        "upload/<int:photo_id>/caption/",
+        views.update_caption,
+        name="update_caption",
+    ),
 ]