Create a lightweight and optimized Minecraft plugin for Paper/Spigot 1.21.1+ named SimpleElevator by Vanny_Chill. The plugin should use iron blocks as elevators: when a player stands on an iron block and sneaks (shift), it checks for another iron block above at the same X and Z and teleports the player to the nearest one after a configurable countdown (default 5 seconds). If the player jumps while standing on the iron block, it should teleport them to the nearest iron block below (down elevator). The teleport should cancel if the player moves or stops sneaking. Add a cooldown system to prevent spam, with a clear cooldown message. Include clean action bar or chat countdown messages. Add nice particle effects (portal/enchant) and sound (Enderman teleport) when teleporting. No permissions required. Support unlimited height (up to max world height). Include a clean startup message in console showing plugin name and author “Vanny_Chill”. The plugin must be simple, smooth, and efficient, with a well-structured config.yml for easy customization of countdown, cooldown, messages, sounds, and particles.