feat: improve navigation behaviour

src/app/ui.py

@@ -106,6 +106,14 @@ class TerminalUI:
                 navigator.collapse_selected_directory()
                 continue
 
+            if key == ord("b"):
+                navigator.go_back()
+                continue
+
+            if key == ord("f"):
+                navigator.go_forward()
+                continue
+
             if key in (curses.KEY_ENTER, 10, 13):
                 navigator.enter_selected_directory()