Function extractDublinCore

extractDublinCore(input: DocumentInput): DublinCoreMetadata
Extract Dublin Core metadata from HTML.
Parameters
- input: DocumentInput
  Parsed HTML document or raw HTML string
Returns DublinCoreMetadata
Dublin Core metadata object
Remarks
Extracts Dublin Core metadata using both DC. and dcterms. prefixes. Fields that can have multiple values (creator, subject, contributor) are extracted as arrays.
Example
```
// With parsed document (recommended for multiple extractions)
const doc = parseHTML(htmlString);
const dc = extractDublinCore(doc);

// Or directly with HTML string
const dc = extractDublinCore(htmlString);
```
- Defined in src/metadata/dublin-core/extract.ts:39