Fix trajectory end index logic to ensure all frames are analyzed when end is -1

Author: harryswift01

CodeEntropy/entropy.py

@@ -247,11 +247,7 @@ def _get_trajectory_bounds(self):
             Tuple of (start, end, step) frame indices.
         """
         start = self._args.start or 0
-        end = (
-            len(self._universe.trajectory) - 1
-            if self._args.end == -1
-            else self._args.end
-        )
+        end = len(self._universe.trajectory) if self._args.end == -1 else self._args.end
         step = self._args.step or 1
 
         return start, end, step