When the server sets MovementFlags::HOVER (SMSG_MOVE_SET_HOVER), the
player now floats 4 yards above the nearest ground surface instead of
standing on it. Uses the existing floor-snap path with a HOVER_HEIGHT
offset applied to the snap target.
- game_handler.hpp: add isHovering() accessor (reads HOVER flag from
movementInfo.flags, which is already set by handleForceMoveFlagChange)
- camera_controller.hpp: add hoverActive_ field and setHoverActive()
- camera_controller.cpp: apply HOVER_HEIGHT = 4.0f offset at floor snap
- application.cpp: sync hover state each frame alongside other movement
states (gravity, feather fall, water walk, flying)