Customizable Player Spawn

  ## Customizable Player Spawn 2.0.0

  Major architecture update for Customizable Player Spawn.

  - Added `schemaVersion=2` profile system
  - Added support for multiple spawn profiles with priorities
  - Added separate configuration layers: placement, terrain, anchor, structure, profile, and postprocess
  - Added structure loading from datapacks, mod resources, world save templates, and external `.nbt` files
  - Added advanced search for valid structure placement positions
  - Added validation for biomes, structure footprint, terrain surface, fluids, dangerous blocks, and height differences
  - Added configurable terrain preparation before structure placement
  - Added structure volume clearing before placement
  - Added support void filling under real structure support blocks
  - Added delayed post-placement processing to reduce issues with plants, block updates, and lighting
  - Added spawn anchor support through marker blocks or structure data markers
  - Added validation for the final player spawn position
  - Kept legacy config as a fallback for compatibility with older modpacks