Fix costume merging, restrict server names, add Centrix tag

- Mod merge: rebuild a merged bundle's chunk metadata the way the game
  writes it (one record per chunk, in chunk GUID order), so costumes
  from different mods built on the same game costume keep their
  textures and meshes
- Merge audit checks that layout, and there is a new unit test for it
- Server names: only letters, numbers, spaces and - _ [ ] ( ),
  1 to 64 characters; the server browser hides servers with other names
- New Centrix tag from the backend's "centrix" list: blue and white
  name, badge and item animation, ranked after Dev and before Creator

Server/README.txt

@@ -38,7 +38,7 @@ straight away (players are told to rejoin). Turn this off with
 
 ReSkateServer.json
 ------------------
-name               Shown in the browser (1-64 characters).
+name               Shown in the browser: 1-64 letters, numbers, spaces and - _ [ ] ( ).
 map                The map everyone skates, named like the game's load command:
                    "San Vansterdam", "Isle of Grom", "Super Ultra Mega Resort",
                    "Stadium 1", or a custom map such as "bbcity" (see Custom maps).

Server/Test/server_config_tests.cpp

@@ -23,6 +23,7 @@ std::string text(const std::filesystem::path &file) {
 
 int run() {
     using namespace dingosdk::server;
+    using dingosdk::valid_server_name;
     const auto folder = std::filesystem::temp_directory_path() / "reskate_server_config_tests";
     std::filesystem::remove_all(folder);
     std::filesystem::create_directories(folder);
@@ -47,6 +48,15 @@ int run() {
     const auto reloaded = load_config(file);
     check(reloaded.name == "Old Server" && !reloaded.boosts && reloaded.votes.map.percent == 60, "Values lost on rewrite");
 
+    // Server names: letters, digits, spaces and - _ [ ] ( ) only.
+    check(valid_server_name("Old Server") && valid_server_name("[EU] Skate_Park-2 (24x7)") && valid_server_name("a"),
+          "A plain server name was refused");
+    check(!valid_server_name("") && !valid_server_name(std::string(65, 'a')) && !valid_server_name("Best! Server") &&
+              !valid_server_name("caf\xC3\xA9") && !valid_server_name("a.b") && !valid_server_name("<b>x</b>") &&
+              !valid_server_name(" padded") && !valid_server_name("padded ") && !valid_server_name("[]--()") &&
+              !valid_server_name("two\nlines"),
+          "A server name with other characters was accepted");
+
     // An up-to-date file is left alone.
     const auto before = std::filesystem::last_write_time(file);
     added.clear();

Server/server_config.cpp

@@ -230,7 +230,7 @@ std::optional<std::uint64_t> parse_scoring(std::string_view text) {
 }
 std::string config_error(const ServerConfig &c) {
     using namespace multiplayer;
-    if (c.name.empty() || c.name.size() > 64 || !valid_member_name(c.name)) return "name must be 1 to 64 characters.";
+    if (!valid_server_name(c.name)) return std::string("name must be ") + server_name_rule + ".";
     if (c.map.empty() || !valid_map_destination(map_destination(c.map)))
         return "map \"" + c.map + "\" is not a known map. Use a name like \"San Vansterdam\", or put the map's mod "
                "folder in Mods next to the server.";

Server/server_host.cpp

@@ -1017,7 +1017,7 @@ std::string Host::command(std::string_view line, std::uint64_t admin) {
         return changed(rotation_text());
     }
     if (name == "name") {
-        if (argument.empty() || argument.size() > 64 || !valid_member_name(argument)) return "Server names are 1 to 64 characters.";
+        if (!valid_server_name(argument)) return std::string("Server names are ") + server_name_rule + ".";
         config_.name = argument;
         if (text::contains_bad_words(config_.name))
             return changed("Server renamed to " + config_.name +