Calls LEGO's cancel_flow assign-variant endpoint and normalizes every outcome — including
network failures, precondition errors, and a timed-out request — into a resolved value.
This function is guaranteed to never reject, so a caller never needs its own try/catch: any
failure mode just becomes { outcome: 'error' | 'timeout' } for the caller to fall back on.
Calls LEGO's cancel_flow assign-variant endpoint and normalizes every outcome — including network failures, precondition errors, and a timed-out request — into a resolved value. This function is guaranteed to never reject, so a caller never needs its own try/catch: any failure mode just becomes
{ outcome: 'error' | 'timeout' }for the caller to fall back on.