Added complete schematic system - save your builds with /schem save, load them with /schem load, manage with /schem list and /schem delete. Upload schematics to public registry with /schem upload (optional password protection), browse public schematics with /schem public, and load shared builds with /schem public load. Permission-based limits for schematic count and size.

Added /preview command - visualize operations before executing them using client-side fake blocks. Preview what /set, /replace, /paste, and /walls will do without modifying the world. Includes area entry prevention, block interaction protection, and auto-cancellation on selection changes. Configurable max blocks, duration, and protection settings.

Added /measure command - displays selection dimensions, volume, and block count.

Added /distance command - calculates Euclidean, block, horizontal, and vertical distances between selection points.