physics: sync all server movement speeds to CameraController

Previously only run speed was synced. Now all server-driven movement
speeds are forwarded to the camera controller each frame:
- runSpeedOverride_: server run speed (existing)
- walkSpeedOverride_: server walk speed (Ctrl key movement)
- swimSpeedOverride_: swim speed (Swim Form, Engineering fins)
- flightSpeedOverride_: flight speed (epic vs normal flying mounts)
- runBackSpeedOverride_: back-pedal speed

Each uses the server value when non-zero/sane, falling back to the
hardcoded WoW default constant otherwise.

include/game/game_handler.hpp

@@ -1155,6 +1155,7 @@ public:
     float getServerWalkSpeed() const { return serverWalkSpeed_; }
     float getServerSwimSpeed() const { return serverSwimSpeed_; }
     float getServerFlightSpeed() const { return serverFlightSpeed_; }
+    float getServerRunBackSpeed() const { return serverRunBackSpeed_; }
     bool isPlayerRooted() const {
         return (movementInfo.flags & static_cast<uint32_t>(MovementFlags::ROOT)) != 0;
     }

include/rendering/camera_controller.hpp

@@ -95,6 +95,7 @@ public:
     void setWalkSpeedOverride(float speed) { walkSpeedOverride_ = speed; }
     void setSwimSpeedOverride(float speed) { swimSpeedOverride_ = speed; }
     void setFlightSpeedOverride(float speed) { flightSpeedOverride_ = speed; }
+    void setRunBackSpeedOverride(float speed) { runBackSpeedOverride_ = speed; }
     void setMovementRooted(bool rooted) { movementRooted_ = rooted; }
     bool isMovementRooted() const { return movementRooted_; }
     void setGravityDisabled(bool disabled) { gravityDisabled_ = disabled; }
@@ -280,6 +281,7 @@ private:
     float walkSpeedOverride_ = 0.0f;
     float swimSpeedOverride_ = 0.0f;
     float flightSpeedOverride_ = 0.0f;
+    float runBackSpeedOverride_ = 0.0f;
     // Server-driven root state: when true, block all horizontal movement input.
     bool movementRooted_ = false;
     // Server-driven gravity disable (levitate/hover): skip gravity accumulation.

src/core/application.cpp

@@ -1012,6 +1012,7 @@ void Application::update(float deltaTime) {
                     renderer->getCameraController()->setWalkSpeedOverride(gameHandler->getServerWalkSpeed());
                     renderer->getCameraController()->setSwimSpeedOverride(gameHandler->getServerSwimSpeed());
                     renderer->getCameraController()->setFlightSpeedOverride(gameHandler->getServerFlightSpeed());
+                    renderer->getCameraController()->setRunBackSpeedOverride(gameHandler->getServerRunBackSpeed());
                     renderer->getCameraController()->setMovementRooted(gameHandler->isPlayerRooted());
                     renderer->getCameraController()->setGravityDisabled(gameHandler->isGravityDisabled());
                     renderer->getCameraController()->setFeatherFallActive(gameHandler->isFeatherFalling());

src/rendering/camera_controller.cpp

@@ -318,7 +318,9 @@ void CameraController::update(float deltaTime) {
     if (useWoWSpeed) {
         // Movement speeds (WoW-like: Ctrl walk, default run, backpedal slower)
         if (nowBackward && !nowForward) {
-            speed = WOW_BACK_SPEED;
+            speed = (runBackSpeedOverride_ > 0.0f && runBackSpeedOverride_ < 100.0f
+                     && !std::isnan(runBackSpeedOverride_))
+                        ? runBackSpeedOverride_ : WOW_BACK_SPEED;
         } else if (ctrlDown) {
             speed = (walkSpeedOverride_ > 0.0f && walkSpeedOverride_ < 100.0f && !std::isnan(walkSpeedOverride_))
                         ? walkSpeedOverride_ : WOW_WALK_SPEED;