Add Playgrounds to Villages for Baby Villagers

Currently, Baby Villagers just run around randomly without much purpose. Adding a Playground structure to generated villages would greatly improve village life and AI behavior.

• New AI Behavior: During the day, Baby Villagers pathfind to the playground to interact with swings, slides, and sandboxes instead of wandering into danger.

• Biome Variations: Playgrounds can adapt to village themes (e.g., Spruce framing for Taiga, Sandstone/Palm for Desert).

• Atmosphere: Makes villages feel much more alive and gives players great vanilla building inspiration!