Dev update: Megaways — up to 117,649 ways (playable)

Added the Megaways mechanic: reels with variable height (2–7 symbols), the number of ways to win recalculates every spin and peaks at 117,649. The math is calibrated via a 1 million spin simulation. The renderer is isolated to avoid affecting existing themes. Play: /megaways How it works — in the blog: /blog/chto-takoe-megaways