Server: object scaling can be turned off

Server: object scaling can be turned off

A dedicated server can stop players resizing the objects they place.

- "allow_object_scaling" in the config's "players" section (default true),
  and "object-scaling on|off" from the console or an admin. A change is
  saved and applies at once.
- Off: the server shares every player's objects at their own size, whatever
  that player's game sent. Admins can still resize theirs, as with the
  object limit.
- The roster tells each game. In the park editor of a player on such a
  server the SCALE mode is not offered, its Y shortcut does nothing, the
  scale box is disabled with a note saying why, and what is placed or edited
  is its own size.
- An object resized before the setting was turned off is its own size for
  everyone else straight away; its owner sees it resized until they edit it.

Extension/Multiplayer/Net/protocol.cpp

@@ -619,6 +619,7 @@ std::vector<std::uint8_t> encode(const Packet &p, bool compact_pose, std::uint32
         w.integer(static_cast<std::uint8_t>(p.object_placement), 1);
         if (!valid_object_limit(p.object_limit)) throw std::invalid_argument("Invalid object limit");
         w.integer(p.object_limit, 2);
+        w.integer(p.object_scaling ? 1 : 0, 1);
         w.integer(p.force_world_layers, 1);
         // One mode per world-layer catalog row; both peers read the same catalog
         // from the same game build.
@@ -945,6 +946,9 @@ std::optional<Packet> decode(std::span<const std::uint8_t> bytes) noexcept {
             const auto object_limit = r.integer(2);
             if (!valid_object_limit(object_limit)) return {};
             p.object_limit = static_cast<unsigned>(object_limit);
+            const auto scaling = r.integer(1);
+            if (scaling > 1) return {};
+            p.object_scaling = scaling != 0;
             const auto forced = r.integer(1);
             if (forced > 1) return {};
             p.force_world_layers = forced != 0;