Gateway admission priority: AuthorizationSnapshot.priority_admission (0 free, 1 paying, 2 Pro). At a full lane's bound a paying caller overflows up to 1.5x and a Pro caller up to 2x an authored bound (1.25x / 1.5x of the worker default lane bound), only on capacity sheds; free callers get the lane_saturated 429, now worded for consumers. Weighted fair-share admission is always on for every bounded rung (GatewayRungDispatchPolicy.fair_share retained only for persisted snapshot identity) (experiential#1193). Split unsigned Messages thinking blocks fold into one Chat reasoning carrier (experiential#1191). Calling-agent attribution headers (experiential#1188). Native unchanged (0.3.129).