feat: add show_in_legal to admin content page editor

- Add "Show in Legal" checkbox to content page editor UI
- Update API schemas (ContentPageCreate, ContentPageUpdate, ContentPageResponse)
- Add show_in_legal parameter to service methods (create_page, update_page, etc.)
- Fix ContentPageNotFoundException to pass identifier correctly
- Fix UnauthorizedContentPageAccessException to use correct AuthorizationException API
- Add comprehensive unit tests for ContentPageService (35 tests)
- Add content page fixtures for testing
- Update CMS documentation with navigation categories diagram

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

tests/conftest.py

@@ -130,4 +130,5 @@ pytest_plugins = [
     "tests.fixtures.marketplace_import_job_fixtures",
     "tests.fixtures.message_fixtures",
     "tests.fixtures.testing_fixtures",
+    "tests.fixtures.content_page_fixtures",
 ]