Archived snapshot

Simplify CITATION.cff so Zenodo's loader accepts it

Both archived releases failed with "Citation metadata load failed".
The file validates against the CFF 1.2.0 schema, but Zenodo's loader
is known to reject a license list; the dual Apache-2.0/CC-BY-4.0 entry
is the prime suspect. The license field now carries the single code
license, the dual licensing moves into the abstract, and the em dash
in the title becomes a hyphen to remove the remaining edge case.