[harshkanhat]

Closes #234

Summary

• Treat a single trailing comma in a flow list as valid YAML syntax and ignore it.
• Report internal empty flow-list items with the frontmatter line number instead of allowing empty strings into catalog data.
• Reject empty quoted block-list items as well.
• Require non-empty strings in the shared string-list schema.

Tests

• Added regression coverage for a trailing flow-list comma, an empty flow-list item, and an empty quoted block-list item.
• The test suite was not run in this environment; CI should verify the changes.

[TMHSDigital]

Thank you! #234 was fixed on main in 4b7fd13 while this was open (one trailing comma ends the list, any other empty item is a line error), so this branch now conflicts and I'm closing it as superseded.

Your minLength: 1 on stringList items in data.schema.json was something main didn't have, so I folded it in (a3cd8b0, with you as co-author). One thing worth knowing: the build validates data.json with a small zero-dependency checker (site/lib/schema-check.mjs) that refuses keywords it doesn't implement, so on current main that change alone stops the build. I added minLength support to the checker in the same commit.