Root cause: LOGIN_VERIFY_WORLD path did not set areaTriggerCheckTimer_ or
areaTriggerSuppressFirst_, so the Stockades exit portal (AT 503) fired
immediately on login, teleporting the player back to Stormwind and crashing
the GPU during the unexpected map transition.
Fixes:
- Set 5s area trigger cooldown + suppress-first in handleLoginVerifyWorld
(same as SMSG_NEW_WORLD handler already did for teleports)
- Add deviceLost_ flag to VkContext so beginFrame returns immediately once
VK_ERROR_DEVICE_LOST is detected, preventing infinite retry loops
- Track device lost from both fence wait and queue submit paths