Ingress proxy timeout now 300s (commit 152230c), so a slow agentic reflect
(~132s) completes before nginx cuts the connection. solar-pro4:free passed
tool-calling + grounded-output probes (t_d0dffc3d). BASE_URL/PROVIDER
unchanged; fallback comment -> stepfun/step-3.7-flash:free.
Refs t_e3375410.