Astaxanthin: A Membrane-Spanning Xanthophyll for Systemic Redox Homeostasis and Mitochondrial Protection Multi-System Antioxidant Targeting Ocular Microcirculation and AMD, Cardiovascular and Cerebrovascular Protection, Reproductive Health, Skin Photo-protection, and Clinically Supported Immunomodulation 0009-0007-5798-1996 DOI: 10.5281/zenodo.16893579