Summary

parseMarkdown (src/core/markdown.ts) and importFromContent (src/core/import-file.ts) assume frontmatter title, type, and slug are strings and cast them with as string. When a page carries a non-string frontmatter value — e.g. a numeric title from a structured JSON import — the unchecked cast lets the wrong type flow into page typing and the content-sanity title check.

Expected

Non-string frontmatter values are coerced to a string (or ignored in favor of the path-derived inference) rather than propagated as the wrong type.

Fix

Defensive coercion in both functions. PR incoming.