Function error_budget_thermal_stacked 

pub fn error_budget_thermal_stacked(
    netlist: &AnalogNetlist,
    cert: &RangeCertificate,
    schedule: &GainSchedule,
    target: &AnalogTarget,
    model: &NonIdealityModel,
    placement: &StackPlacement,
    map: &ThermalMap,
    stack: &StackTarget,
    opts: &ThermalOpts,
) -> OutputBudget

The thermally-coupled stacked budget: the stacked budget PLUS the drift terms priced against the CERTIFIED thermal map — offset drifts with each tile’s absolute rise (offset_tempco · ΔT), gain with the tile-to-operand GRADIENT (gain_tempco · |ΔT_cell − ΔT_operand|) — matching cares about gradients. One Picard pass, deterministic: placement + power → temperature → ε; hot placement provably costs ε (thermal_cooking_lock measures it). The ℚ→f64 bridge rounds outward.