added Trajectory::NormalizedDirection

Framework/Geometry/Trajectory.h

@@ -47,6 +47,11 @@ namespace corsika::geometry {
     void LimitEndTo(corsika::units::si::LengthType limit) {
       fTimeLength = T::TimeFromArclength(limit);
     }
+    
+    auto NormalizedDirection() const {
+        static_assert(std::is_same_v<T, corsika::geometry::Line>);
+        return T::GetV0().normalized();
+    }
   };
 
 } // namespace corsika::geometry