Dev E active-flux lane (E2b): F-eta active-flux observer (shared szl_cuas_formulas, byte-identical to killinchu) + a11oy_active_flux_router module (/api/a11oy/v1/router/active-flux-crossover,sweep,info + /v1/... proxy mirror + /router-crossover page) + serve.py registration + Dockerfile COPY. Deterministic complement to RouteLLM bandit. MODELED; Lambda=Conjecture1; Khipu/BFT=Conjecture2; adds nothing to locked-8.