Lesson metadata: Add maintainer, once decided that we do it this way #347

Current lesson maintainer(s) will be collected in the contact field of CITATION.cff (same person format as authors). That field isn't yet filled or carried through to the other two places lesson metadata ends up: bioschemas.yml and the Zenodo record created at release time.

What needs to be done

• bioschemas.yml : update get_schema_info_from_cff.py so it also maps contact → schema.org's maintainer property (the closest semantic fit), alongside the existing name/authors/version/license/identifier mapping. Regenerate bioschemas.yml afterwards to confirm the output looks right.

• Zenodo : our deposits go through a custom release workflow (using the ZENODO_TOKEN/ZENODO_CONCEPT_ID secrets), not GitHub's built-in Zenodo integration, so nothing currently carries contact over automatically. Then add contact as a contributors entry with the DataCite/Zenodo contributor type ContactPerson.