Magnets...but with a difference
Magnets to attach the power wires.
Yes they have been suggested and found to be too strong to just pull off but...don't just arrange for them to direct pull.
Magnets are strong close up, but the pull drops off rapidly so only small motion is needed. Thus arrange for the lead wires to run along a lever so that the force to pull the connections is minute.
Keep the wires and levers lightweight but stiff (carbon fiber etc.) so they don't contribute significant force on t6he magnets during jiggling.
---------------------------------------- rear face of rocket
..........................O
_____________O__V_
(
)
Key: (=wire. _ = lever O=magnet pair with contacts between V=fulcrum fixed to rocket ....=space so the ascii art works.
At rest, there is a small gap between the lever and the fulcrum point. As the rocket starts to move, the feed wire tensions, loads the lever that can rock until the fulcrum makes contact and the magnet is popped apart and hangs free. The end of the lever could even strike a tag fixed to the flying truss instead of loading the wires.