Fix GPU resource leaks and re-entrant world loading for instance transitions

Reset descriptor pools in CharacterRenderer/M2Renderer/WMORenderer on map
change to prevent VK_ERROR_DEVICE_LOST from pool exhaustion. Defer re-entrant
SMSG_NEW_WORLD during active world load to avoid recursive cleanup crashes.
Gate swim bubbles on swimming state, skip redundant shadow pipeline re-init,
add WOWEE_SKIP_* env vars for render isolation debugging.

src/rendering/swim_effects.cpp

@@ -557,7 +557,9 @@ void SwimEffects::update(const Camera& camera, const CameraController& cc,
     }
 
     // --- Bubble spawning ---
-    bool underwater = camWaterH && camPos.z < *camWaterH;
+    // Require swimming state to prevent spurious bubbles on login/teleport
+    // when camera may briefly appear below a water surface before grounding.
+    bool underwater = swimming && camWaterH && camPos.z < *camWaterH;
     if (underwater) {
         float bubbleRate = 20.0f;
         bubbleSpawnAccum += bubbleRate * deltaTime;