in order to use concave shapes with jit.phys.body, you need to send a matrix of points describing the shape to the object.
check out the "matrix" tab of the phys.body help file for more info.
i've updated your patch to show proper usage of this technique.
notice the use of @shape dynamicmesh and @kinematic 1
dynamicmesh will allow you to update your point matrix dynamically (possibly not necessary for your needs)
enabling kinematic will allow you to apply position and rotation transformations to the rigid body.
we use jit.gl.mesh to draw the shape.