Dietary Nitrate Bioactivation at the Diet–Microbiota–Host Interface: The Enterosalivary Cycle, Food Matrix, Microbial Determinants and Health Implications—A Narrative Review Supported by a Structured Literature Search - Gilda-Diana Buzatu; Ana-Maria Dodocioiu; Eleonora Daniela Ciupeanu-Călugaru; Dumitru Radulescu; Emil-Tiberius Trască (Nutrients, 2026)