Function bakuAcceleration

Creates an acceleration method implementing the FIDE C.04.7 Baku Acceleration.

Splits players into two groups — GA (top half) and GB (rest) — and adds virtual points to GA players' scores in the first rounds, causing stronger players to face each other earlier.

Virtual points affect pairing only — they are never stored in the game history or reflected in standings.

• First half of accelerated rounds: GA players get 1 virtual point.
• Second half of accelerated rounds: GA players get 0.5 virtual points.
• After accelerated rounds: 0 virtual points.
• GB players: always 0 virtual points.