Could be done with a double-pole double-throw "micro-switch"
You would want to be sure not to flip switch on the actuating channel with the motor running.
The wiring is very simple. Used in model railroading for reversing a section of track.
Pick 2 of the 3 wires from ESC and connect to the common pins of each side of the DPDT switch.
Pick 2 of the 3 motor wires and connect to one side output of the switch.
Take jumpers from the other outputs of the switch and crossover back to the other outputs.
I can draw it up in paint in a couple of minutes.