chore: add documentation RI

Code functionality left unchanged, only added docs where missing

close: N25B-298

src/robot_interface/utils/qi_utils.py

@@ -8,6 +8,12 @@ except ImportError:
 
 
 def get_qi_session():
+    """
+    Create and return a Qi session if available.
+
+    :return: The active Qi session or ``None`` if unavailable.
+    :rtype: qi.Session | None
+    """
     if qi is None:
         logging.info("Unable to import qi. Running in stand-alone mode.")
         return None