Writes a motor policy into the current project.
mix monty_cad.gen.policy follow_chamfersTwo files: lib/<app>/plugins/follow_chamfers.ex — the callbacks
Monty.Frameworks.Models.MotorPolicies.MotorPolicy requires, and the
describe/0 a cluster asks for — and a test that asserts both. call/6 raises
until the decision is written, on purpose: a generated body that looks like an
answer is a decision nobody made.
The policy is :owner_only, because a policy over a CAD part reads a B-rep
handle and that cannot leave the node that opened it. A policy over something
else changes the description and says why.