fix(seed): drop meta_keywords reference (column removed in cms_003)

Migration cms_003 dropped meta_keywords from content_pages but the
default-pages seed script still passed it to ContentPage(...), so
make db-reset / fresh seeding bombed on the first platform.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

scripts/seed/create_default_content_pages.py

@@ -2979,7 +2979,6 @@ def _create_page(
         template=page_data.get("template", "default"),
         sections=sections,
         meta_description=page_data.get("meta_description", ""),
-        meta_keywords=page_data.get("meta_keywords", ""),
         is_platform_page=is_platform_page,
         is_published=True,
         published_at=datetime.now(UTC),