SAN FRANCISCO — Travelers worldwide may love using Airbnb to book vacation stays, but the company that revolutionized home-sharing faces a hostile ballot measure in the city where it was founded.Proposition F on the Nov. 3 San Francisco ballot would limit short-term rentals to 75 days a year and require hosting companies such as Airbnb to yank listings that violate the limit.The city would be required to notify neighbors when a person registers to host. The measure would enable pricey lawsuit damages against …