Skyveil Cloudlands Pass 11

Added cloud water absorption: normal Skyveil cloud blocks can random-tick scan up to 20 blocks directly below for a water source, evaporate that water source, and convert into rain_cloud. This is intentionally vertical-column and short-range so it does not drain normal biomes.

Added Red Sprites: storm-only Cloudlands hostile mobs that chase Allays. They render as small neon-red transparent cloud-like sprites, emit red lightning particles during storms, and are intended to be killed by snowballs. Default: 10 snowball hits.

Added Happy Ghast defense helper: if the configured Happy Ghast entity id exists in the current game/modpack, nearby Happy Ghasts periodically spit snowballs at Red Sprites during storms.

Added /skyveilcloudlands populate_red_sprites_near <radius> for testing.
