v0.17.2 — errored roots revive themselves

• Errored roots revive themselves: a provider turn failure left the orchestrator thread in error state indefinitely — auto-resume (0.16.3) only reconciled the goal once the root ran again, and nothing restarted it. The pulse now revives an errored root with exponential backoff (2m doubling to a 30m cap, reset on a real turn), completing the self-healing set: workers three-strike restaff, wedged root turns get stopped, blocked goals reconcile on recovery, and dead roots restart.