Function getCuratedTitle

Resolve the best card title for a given methodology / template / reference file and language.

Lookup priority:

1. Curated per-language title from CURATED_TITLES (preferred — this is where all 14-language localization is maintained)
2. Curated English title from CURATED_TITLES (.en overlay)
3. Per-entry titleI18n[lang] on a CURATED_DESCRIPTIONS entry (legacy path; retained so future entries can colocate title + desc)
4. Per-entry title on a CURATED_DESCRIPTIONS entry
5. fallback — the H1-extracted title from the source Markdown

The generator always ships fallback from the Markdown H1 so this function is guaranteed to return a non-empty string for every file in the library, even when the curated tables have no entry yet.