std_msgs/Header header
bool    tracking_active      # false when no target is locked
uint32  track_id             # persistent ID across frames
float32 bearing_deg          # horizontal bearing to target (°, right=+, left=−)
float32 distance_m           # range to target (m); 0 = unknown / depth invalid
float32 confidence           # 0.0–1.0 overall track quality
int32   bbox_x               # colour-image bounding box (pixels, top-left origin)
int32   bbox_y
int32   bbox_w
int32   bbox_h
float32 vel_bearing_dps      # bearing rate   (°/s, from Kalman velocity state)
float32 vel_dist_mps         # distance rate  (m/s, + = moving away)
uint8   depth_quality        # 0=invalid 1=extrapolated 2=marginal 3=good
