Add Zenodo release metadata

[galjos]

Summary

• Add Zenodo and CFF citation metadata.
• Align package license metadata with the existing LGPL license.
• Document Zenodo verification in the release process.

Validation

• CFF 1.2 schema validation passed.
• 415 passed, 16 skipped.
• Package build completed without license warnings.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 97.40%. Comparing base (9ac88db) to head (5056c78).

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #126   +/-   ##
=======================================
  Coverage   97.40%   97.40%           
=======================================
  Files          32       32           
  Lines        2001     2001           
=======================================
  Hits         1949     1949           
  Misses         52       52           

Flag	Coverage Δ
unittests	97.40% <ø> (ø)

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