Gladiator arena: gold economy, outfitting shop, permadeath runs

Turns the sandbox into a survival roguelike loop: outfit your gladiator
with banked gold, enter the arena, earn gold from kills and wave clears,
die, keep 10% of your total value (floored at the 500 fresh-start).

Economy (GameState autoload):
- banked_gold, owned items, and loadout persist to user://save.cfg
- Kill gold (basic 10g, armed 25g) credited server-side to the killer
- Wave-clear bonus (25 + 5/wave) for all players; wave synced to peers
- Death settlement liquidates gear, guarded against double-fire

Character creation / shop:
- Menu reframed: armory shop + live Character Sheet loadout preview
- Character Sheet gains preview mode (renders from loadout, no player)
- Buy/Equip with hand rules; two-handers and off-hands displace each
  other symmetrically (shop and in-game pickups)
- Chosen loadout auto-equips on spawn via existing RPC path

Combat feel:
- Attacks snap to camera facing and lock direction for the swing
- Dash commits to its direction for the full duration
- Weapon slots show name text when no icon is set
- Hitbox/hurtbox debug meshes hidden by default (H toggles)

Death is final: players no longer respawn; a results screen shows waves,
time, kills, and the settlement, then returns to camp. Armed enemies no
longer respawn (were an infinite gold farm and respawned invisible).

level/scripts/3d_godot_robot.gd

@@ -13,6 +13,10 @@ func apply_rotation(_velocity: Vector3) -> void:
 
 	# rpc("sync_player_rotation", new_rotation_y)
 
+## Instantly face a direction (no lerp) - used to lock attacks to camera facing
+func snap_rotation(_direction: Vector3) -> void:
+	rotation.y = atan2(-_direction.x, -_direction.z)
+
 func animate(_velocity: Vector3) -> void:
 	# Don't override attack animation if it's playing
 	if animation_player.is_playing() and animation_player.current_animation == "Attack1":