Metadata Format Regression Check

This fixture exists to catch regressions in frontmatter normalization, not to be a real article. It intentionally mimics common CMS authoring mistakes:

Why this fixture exists

• date and updated are unquoted YAML date scalars, which parse to native Date objects rather than strings -- the exact shape that previously broke the published date on the live site.
• categories is written as a single bare value, not a YAML list.
• tags includes leading/trailing whitespace, a case-insensitive duplicate, and an empty string, all of which should be cleaned up.

What a passing build confirms

If the build succeeds and this page renders a real date and a single "Guides" category badge with two deduplicated, trimmed tags, the frontmatter normalization fix is working correctly.