physics: block client-side movement when server roots the player

When SMSG_FORCE_MOVE_ROOT sets ROOT in movementInfo.flags, the
camera controller was not aware and continued to accept directional
input. This caused position desync (client moves, server sees player
as rooted).

- Add movementRooted_ flag to CameraController with setter/getter.
- Block nowForward/nowBackward/nowStrafe when movementRooted_ is set.
- Sync isPlayerRooted() from GameHandler to CameraController each
  frame alongside the existing run-speed sync in application.cpp.
- Add GameHandler::isPlayerRooted() convenience accessor.

include/rendering/camera_controller.hpp

@@ -92,6 +92,8 @@ public:
     void setMovementCallback(MovementCallback cb) { movementCallback = std::move(cb); }
     void setUseWoWSpeed(bool use) { useWoWSpeed = use; }
     void setRunSpeedOverride(float speed) { runSpeedOverride_ = speed; }
+    void setMovementRooted(bool rooted) { movementRooted_ = rooted; }
+    bool isMovementRooted() const { return movementRooted_; }
     void setMounted(bool m) { mounted_ = m; }
     void setMountHeightOffset(float offset) { mountHeightOffset_ = offset; }
     void setExternalFollow(bool enabled) { externalFollow_ = enabled; }
@@ -268,6 +270,8 @@ private:
 
     // Server-driven run speed override (0 = use default WOW_RUN_SPEED)
     float runSpeedOverride_ = 0.0f;
+    // Server-driven root state: when true, block all horizontal movement input.
+    bool movementRooted_ = false;
     bool mounted_ = false;
     float mountHeightOffset_ = 0.0f;
     bool externalMoving_ = false;