physics: implement HOVER movement flag physics in CameraController

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)

src/core/application.cpp

@@ -1018,6 +1018,7 @@ void Application::update(float deltaTime) {
                     renderer->getCameraController()->setFeatherFallActive(gameHandler->isFeatherFalling());
                     renderer->getCameraController()->setWaterWalkActive(gameHandler->isWaterWalking());
                     renderer->getCameraController()->setFlyingActive(gameHandler->isPlayerFlying());
+                    renderer->getCameraController()->setHoverActive(gameHandler->isHovering());
                 }
 
                 bool onTaxi = gameHandler &&