add listen

agent.py

@@ -114,7 +114,7 @@ VALID GAME COMMANDS for play_action:
 - Objects: take <item>, drop <item>, open <thing>, close <thing>, examine <thing>, put <item> in <container>, pull <object>, push <object>
 - Light: turn on lamp, turn off lamp
 - Combat: attack/hit <enemy> with <weapon> (swords, axes, etc.)
-- Other: inventory, look, read <thing>, wait, ask <character> about <topic>, give <item> to <character>
+- Other: inventory, look, read <thing>, wait, ask <character> about <topic>, give <item> to <character>, listen
 
 FORBIDDEN (will NOT work): check, inspect, search, grab, use, help