Protection: applies WorldConfig flags to disable PvP and fall damage, and forces every connecting player to GameMode.Adventure (no block break/place).
Welcome message: privately sent to each joining player.
Join announcement: broadcast to everyone else on this server.
Spawn-on-join: every player is teleported to the world's configured spawn point on join. No more "where did I end up" after a transfer.

Requires

NetworkCore loaded (for the plugin dependency declaration; Hub doesn't actually use any NetworkCore services at runtime in v1, but the manifest expresses the order).

Why this is critical

Hubs are where players land. If they:

Can break/place blocks: they grief the lobby.
Don't spawn at spawn: they end up wherever they last logged out, often outside the playable area.
Don't get a welcome: the server feels broken on first visit.

So the hub behaviors aren't optional polish - they're the user's first impression of the network.

Read before changing

docs/01_Overview.md - architecture
docs/02_Configuration.md - config.json fields
docs/03_Limits_and_Gotchas.md - what we can't (yet) protect against

Where this is NOT installed

Don't install Hub on minigame servers, persistent worlds, or anywhere players are supposed to actually do things. Its protection flags will lock the world to read-only mode. It's a hub-only plugin.