Addresses code review feedback on PR #20 to eliminate redundant validations and tighten interface matching logic.

Changes

• Interface matching precision: Changed "title" in interface.lower() to interface_lower == "title" to prevent false matches on "subtitle", "entitle", etc.

• Excerpt validation loop: Break after first successful reference field match to avoid N validations when multiple reference fields contain values

• Title validation loop: Validate only first available title against first available reference instead of all combinations (prevents N×M duplications)

• Class documentation: Updated ReferenceValidationPlugin docstring to reflect title validation capabilities and dcterms:title field discovery

• Test coverage: Added test_validate_title_only_fetch_fails() for when fetcher.fetch() returns None

Example

Before: Instance with 2 title fields and 2 reference fields → 4 validation calls
After: Instance with 2 title fields and 2 reference fields → 1 validation call (first title × first reference)

✨ Let Copilot coding agent set things up for you — coding agent works faster and does higher quality work when set up for your repo.