Still Behind You

First upload of the 1.21.1 and 1.20.1 builds.

• Workstations you placed follow you whenever nobody can see them.
• A follower is held still while any player can see it, not just its owner.
• Third-person aware: the server rebuilds the F5 camera, so nothing drops into shot behind your own head. Needs the mod on that client; vanilla clients are treated as first person.
• Inventories, burn timers and part-finished smelts survive the move. Double chests move as one piece.
• Craft a Restraining Order (paper + red dye) to pin one permanently.

Marked alpha because it has not been playtested yet. It builds and runs a dedicated server on all six loader/version combinations, but no one has watched a block arrive in game.