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.

include/ui/game_screen.hpp

@@ -237,6 +237,7 @@ private:
     void renderGuildBankWindow(game::GameHandler& gameHandler);
     void renderAuctionHouseWindow(game::GameHandler& gameHandler);
     void renderDungeonFinderWindow(game::GameHandler& gameHandler);
+    void renderInstanceLockouts(game::GameHandler& gameHandler);
 
     /**
      * Inventory screen
@@ -269,6 +270,9 @@ private:
     int bagBarPickedSlot_ = -1;   // Visual drag in progress (-1 = none)
     int bagBarDragSource_ = -1;   // Mouse pressed on this slot, waiting for drag or click (-1 = none)
 
+    // Instance Lockouts window
+    bool  showInstanceLockouts_ = false;
+
     // Dungeon Finder state
     bool  showDungeonFinder_ = false;
     uint8_t lfgRoles_ = 0x08;  // default: DPS (0x02=tank, 0x04=healer, 0x08=dps)