One billion dollars is again being dangled to anyone who can successfully put together a perfect March Madness bracket. Kalshi — the prediction market platform that has burst onto the sports scene — is ponying up the dough, offering a $1 billion bounty for anyone who correctly predicts all 63 games of the 2026 March Madness tournament, The Post has learned. An announcement is expected on Monday, and any participants will need to sign up and create an account on Kalshi to take part in the