SMSG_MOVE_WATER_WALK / SMSG_MOVE_LAND_WALK now correctly set/clear
WATER_WALK (0x00008000) in movementInfo.flags, ensuring the flag is
included in movement ACKs sent to the server.
In CameraController, when waterWalkActive_ is set and the player is
at or above the water surface (within 0.5 units), clamp them to the
water surface and mark as grounded — preventing water entry and allowing
them to walk across the water surface as the spell intends.