完善客户端功能并同步差距文档

project/ui/ground_items.gd

@@ -118,6 +118,24 @@ func try_pickup() -> int:
 		client.pickup_item(best_vid)
 	return best_vid
 
+# Mouse hover probe used by PlayerController's cursor state. Ground drops are
+# deliberately tested in screen space, so clicking a visible label / mesh
+# selects PICK even when the item is not the nearest drop in world distance.
+func hover_at(camera: Camera3D, screen_pos: Vector2) -> bool:
+	if camera == null:
+		return false
+	var best := INF
+	for node in _by_vid.values():
+		if not is_instance_valid(node):
+			continue
+		if camera.is_position_behind(node.global_position):
+			continue
+		var p := camera.unproject_position(node.global_position + Vector3(0, 0.35, 0))
+		var d := p.distance_to(screen_pos)
+		if d <= 28.0:
+			best = minf(best, d)
+	return best < INF
+
 func _name_for(vnum: int) -> String:
 	if proto:
 		var pd: Dictionary = proto.item(vnum)