Ground items do not get replicated to party joiners by the leader

[HybridEidolon]

This depends on correct handling of item unique IDs during transfer from a lobby to a party. This is a lot more complicated than simply being unique IDs between users: the IDs change based on the player's slot in the party, and also whether or not it was generated for a drop on the ground (i.e. stack drops from inventory, enemy and box drops). They also get reassigned when going back to the lobby or logging out.

In the current implementation, item IDs are handled correctly, but for whatever reason, a joining player will not see all the existing items on the ground. Having asserted that the subcommand messages sent during the party burst to a joiner are symmetrical, I do not understand why this is happening. The party leader is responsible for sending info about what items are on the ground, but the joiner is not getting this information. It may be related to item IDs.

A brute-force solution would be to simply send information about all the party inventory items (ground items) on join, but this is not technically correct; the client would see the "freshly dropped" particle effects if, for example, the item were on the ground inside the Hunter's Guild.