AI Opponent Implementation

Help implement or tune AI opponent logic per the game design.

AI Strategy (from design doc)

func chooseAcceleration(racer: Player, track: Track, opponents: [Player]) -> GridVector {
    var bestScore = Int.min
    var bestAccel = GridVector(0, 0)

    for acceleration in allAccelerations {
        let newPos = racer.position + racer.velocity + acceleration
        let newVel = racer.velocity + acceleration