48a6049dc6
Smallest-scope realisation of spec §"Built-in schedules" Damped: a ConvergenceOptions::alpha field plumbed through run_chain to a new Gaussian::damp_natural helper applied inside TruncFactor and MarginFactor's propagate. alpha=1.0 default keeps every existing golden bit-equal; alpha<1.0 stabilises oscillating fixed-point loops on hard graphs. Defers Schedule trait integration, nat-param convergence switch, oscillation auto-detect, Residual/OneShot, and Synergy/ScoreFactor — each gets its own future plan.