Add category-list factory and seed categories in B4W smoke test

tests/conftest.py

@@ -87,13 +87,19 @@ def populated_db_b4w(
     Only the first-layer ingestion table is filled; no further processing.
     ``**kwargs`` are forwarded to ``B4wExportFactory.build``; callable values
     are resolved per row (e.g. ``ValDt=lambda: faker.date_between(...)``).
+    An optional ``setup`` callback runs after database creation and before rows
+    are inserted.
     ``Id1`` is reserved: it is set per row (``1..row_count``) and cannot be
     overridden via ``**kwargs``.
     The returned session is *not* closed by the fixture; close it in the test.
     """
 
     def populate_db_b4w(
-        name: str, row_count: int = DEFAULT_B4W_ROWS, **kwargs: Any
+        name: str,
+        row_count: int = DEFAULT_B4W_ROWS,
+        *,
+        setup: Callable[[Session], None] | None = None,
+        **kwargs: Any,
     ) -> Session:
         if "Id1" in kwargs:
             raise ValueError(
@@ -101,6 +107,8 @@ def populated_db_b4w(
                 "cannot be overridden via **kwargs"
             )
         session = db_session_factory(name)
+        if setup is not None:
+            setup(session)
         for i in range(row_count):
             row_kwargs = {k: (v() if callable(v) else v) for k, v in kwargs.items()}
             row = B4wExportFactory.build(Id1=i + 1, **cast(dict[str, Any], row_kwargs))