fix cash in multiplayer (#97)

* replicate it
* use collision observer to simplify
* pass entity of player that receives cash for a duplicate head

crates/hedz_reloaded/src/protocol/mod.rs

@@ -6,7 +6,7 @@ use crate::{
     animation::AnimationFlags,
     backpack::{Backpack, BackpackSwapEvent},
     camera::{CameraArmRotation, CameraTarget},
-    cash::CashInventory,
+    cash::{Cash, CashInventory},
     character::{AnimatedCharacter, HedzCharacter},
     control::{
         CashHealPressed, ClientInputs, ControllerSettings, Inputs, SelectLeftPressed,
@@ -106,6 +106,7 @@ pub fn plugin(app: &mut App) {
         .replicate::<SquishAnimation>()
         .replicate_once::<Transform>()
         .replicate_once::<SpawnTrail>()
+        .replicate_once::<Cash>()
         .replicate_as::<Visibility, SerVisibility>();
 
     app.replicate_once::<ThrownProjectile>()