Reimplement gacha

[Yostarcc]

1. Fix calculation logic for the gacha guarantee system
2. Implement the beginner gacha banner
3. Migrate gacha histories to a dedicated gacha_histories table
4. Implement an approximate gacha probability algorithm based on official rules.
   My test script
   A 100,000,000-pull simulation was executed against the current implementation (banner 10145):
   • 5★ overall rate: 2.223084% (official: 2.247%, delta: -0.023916%)
   • Featured 5★ overall rate: 1.225664% (official: 1.250%, delta: -0.024336%)
   • 4★+ overall rate: 15.161929% (official: 14.600%, delta: +0.561929%)
   • On 10th-pity-trigger pull: 5★ rate 2.221446% (official: 2.000%, delta: +0.221446%),
     4★ rate 97.778554% (official: 98.000%, delta: -0.221446%)