fix(catalog): expose edition_normalize_publisher_imprint migration

Add a 'edition_normalize_publisher_imprint' case to the catalog
management command's migrate dispatcher so the
edition_normalize_publisher_imprint_20260428 helper can actually be
invoked from the CLI:

    ./manage.py catalog migrate \
        --name edition_normalize_publisher_imprint [--batch-size N]

Mirrors the existing populate_credits / populate_credits_extra wiring.

Author: Your Name

catalog/management/commands/catalog.py

@@ -200,6 +200,12 @@ def migrate(self, m, start=None, batch_size=1000):
                 from catalog.common.migrations import populate_credits_extra_20260415
 
                 populate_credits_extra_20260415(batch_size=batch_size)
+            case "edition_normalize_publisher_imprint":
+                from catalog.common.migrations import (
+                    edition_normalize_publisher_imprint_20260428,
+                )
+
+                edition_normalize_publisher_imprint_20260428(batch_size=batch_size)
             case _:
                 self.stdout.write(self.style.ERROR("Unknown migration."))