Theory — the Learn source

docs/theory/01–10 is the single source for both this site and SAGE Labs' Learn mode (write once, render twice). The ten explainers, in order: softmax and λ · the fixed point · QRE vs mixed Nash · MaxEnt · Gibbs and potential games · detailed balance and currents · reciprocity · elasticity vs λ · the one-price objection · the same machinery everywhere. Authored during Stage 4 Track D.