feat(opportunities): add protected batch synchronization endpoint

feat(collectors): add Erasmus Mundus collector

feat(collectors): add Campus France collector

feat(collectors): add African Union opportunities collector

feat(collectors): add University of Bamenda collector

feat(collectors): add University of Dschang collector

feat(collectors): add University of Douala opportunity collector

feat(collectors): add University of Buea opportunity collector

feat(collectors): add MINESUP collector validation

feat(opportunities): add official UNESCO internships collector

fix(opportunities): improve Mastercard Foundation collector

fix: pass source slug during opportunity synchronization

feat: synchronize Chevening opportunities with Neon

feat(opportunities): add verified opportunities API

feat: initialize VerifPulse FastAPI backend