DG: Natural Reproduction

Added

• Autonomous Gestation Timers & Prenatal Pasture Vitality: Introduced dynamic pregnancy countdowns and prenatal nutrition mechanics:
  • Pregnancy Countdown: Breeding enters mothers into active gestation (default 24000 ticks = 1 in-game day), emitting occasional warmth particles (HAPPY_VILLAGER / HEART) and preventing immediate repeat breeding.
  • Dynamic Prenatal Pasture Care: Mothers spending their pregnancy in enriched pastures deliver calves with the "Prenatal Vitality" trait (+15% max HP, +10% movement speed, +10% scale recovery up to 1.30x).
  • Native Egg Laying Synergy: Oviparous species lay native egg blocks upon completing gestation (Frogs lay Blocks.FROGSPAWN, Turtles lay Blocks.TURTLE_EGG, Sniffers lay Blocks.SNIFFER_EGG, Chickens lay eggs).
• AnimalGestationHelper: Created single-purpose utility class managing gestation countdowns, prenatal enrichment checks, and egg delivery.
• Dedicated GameRules: Registered natural-reproduction:gestation_period (Boolean, default true), natural-reproduction:manual_gestation (Boolean, default true), and natural-reproduction:gestation_duration (Integer, default 24000 ticks), integrated into /gamerule, /naturalreproduction command suite, and YACL screen.