A cycle rejected everything still waiting, not just the modules on it. One that
merely says 'after B' is not itself circular, and once B is dropped its relation
has nothing to wait for -- the same as naming a module that was never installed.
Now only the ids that can reach themselves are dropped, and a dropped id stops
being a dependency so the damage stops rather than spreading downstream.
A relation could also overturn the stage order: 'load after conditioning' was
honoured, putting a whole stage out of sequence to satisfy one module. Stage is
the coarse order; an impossible relation is dropped and logged, and the module
itself is kept.
panels.js now keeps what a module's setup() returns, which is its unsubscribe --
discarding it leaves a live listener behind on every re-mount.
digital-garbage
e2661a3965