Constant REDUCER_INPUT_CAPACITY 

const REDUCER_INPUT_CAPACITY: usize = 64;

Reducer input channel depth.

Sizing rationale: a single agent’s peak burst during one rollout cycle is roughly:

• 1 LocalActivate (from longpoll)
• 1 LocalActivationStarted + 1 LocalActivationCompleted
• per declared probe (~1–10): LocalProbeObservedFirst then LocalProbeResult every interval until soak elapses
• 1 LocalConvergedReached 32 covers the spike comfortably; 64 doubles for slack. The CP side uses 1024 because one CP fans 256 hosts; one agent only fans itself.