Dedicated server: park mods as server-owned objects

- maps.park_mods binds a Park Editor park mod (Mods/<folder>/parks/<key>.park.json)
  to a name and the map it was built on; maps.park_limits caps the parks and
  objects spawned at once (3 and 512 by default)
- park-mod list | add <name> [<name>...] [minutes] | remove <name> [<name>...] | clear,
  from the console, as /park-mod by admins, and by players through custom votes
- A spawned park is the layout of the server's own SteamID and epoch, sent like a
  player's: games since 1.0.0 already show it, it counts against no player's
  object limit, nobody can move or delete it, and it stays when players leave
- Objects players' games would not take (not Build Kit items, broken values) are
  skipped and logged; a missing or broken park is an error line when spawning
- Optional expiry (1-1440 min) with a warning in chat a minute before; every
  park goes on a map change and none survive a restart
- [parks] log lines name who did it: console, the admin, or "a vote"; a vote's
  refusal reaches chat
- park-mod is reserved for custom commands; README.txt documents the settings,
  commands and a park/unpark vote

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Y2G4APEkhHgVs59RDL3XWD

Server/server_engine.cpp

@@ -176,6 +176,13 @@ bool ServerEngine::load_environment(const std::filesystem::path& folder, const s
             renamed = true;
         }
     }
+    for (auto &park : config_.park_mods) { // and so are the maps the park mods belong to
+        if (const auto *level = find_level(park.map); level && level->name != park.map) {
+            park.map = level->name;
+            renamed = true;
+        }
+    }
+    config_.mods = folder_ / "Mods";
     if (renamed) try { save_config(config_); } catch (...) {}
     if (const auto error = config_error(config_); !error.empty()) {
         std::string err = "Config problem: " + error;