rendering: drive Run/Stand animations from actual movement state

CameraController now transitions the player character to Run (anim 4)
on movement start and back to Stand (anim 0) on stop, guarded by a
prevPlayerMoving_ flag so animation time is not reset every frame.
Death animation (anim 1) is never overridden.

Application creature sync similarly switches creature models to Run (4)
when they move between server positions and Stand (0) when they stop,
with per-guid creatureWasMoving_ tracking to avoid per-frame resets.

include/rendering/camera_controller.hpp

@@ -226,6 +226,9 @@ private:
     bool autoRunning = false;
     bool tildeWasDown = false;
 
+    // Movement animation state tracking
+    bool prevPlayerMoving_ = false;
+
     // Movement state tracking (for sending opcodes on state change)
     bool wasMovingForward = false;
     bool wasMovingBackward = false;