Rate-Distortion View of RSA (Stub)

@cite{cover-thomas-2006} @cite{zaslavsky-hu-levy-2020}

Formalizes the main results from @cite{zaslavsky-hu-levy-2020}, "A Rate-Distortion view of human pragmatic reasoning" (arXiv:2005.06641).

Results (to be restated for RSAConfig)

1. Proposition 1 (SM §B, Eq. 7-9): RSA dynamics implement alternating maximization of G_α. Each step is an argmax, so G_α is monotonically non-decreasing across iterations.

2. Proposition 2 (main text p.3): E[V_L] can decrease even as G_α increases — disconfirming the conjecture that RSA maximizes expected listener utility.

3. Proposition 3 (SM §C): Phase transition at α = 1.

Old RSAScenarioQ-based proofs removed; restate using RSAConfig.