Add Instance Lockouts window and fix three compiler warnings

- Add Escape Menu → Instance Lockouts button opening a new panel
  that lists active lockouts with instance name (from Map.dbc),
  difficulty, time-until-reset countdown, and locked/extended status.
  map name lookup is cached on first open.
- Fix uninitialized ChatType in sendChatMessage (default to SAY)
- Remove unused startWorld variable in handleMonsterMoveTransport
- Remove unused modelCached variable in spawnOnlineCreature
  Eliminates all -Wunused-but-set-variable and -Wmaybe-uninitialized
  warnings in the main translation units.

src/game/game_handler.cpp

@@ -11525,7 +11525,6 @@ void GameHandler::handleMonsterMoveTransport(network::Packet& packet) {
 
     if (hasDest && duration > 0) {
         glm::vec3 destLocalCanonical = core::coords::serverToCanonical(glm::vec3(destLocalX, destLocalY, destLocalZ));
-        glm::vec3 startWorld = transportManager_->getPlayerWorldPosition(transportGuid, startLocalCanonical);
         glm::vec3 destWorld  = transportManager_->getPlayerWorldPosition(transportGuid, destLocalCanonical);
 
         // Face toward destination unless an explicit facing was given