RL weight update. Called by the plugin after approve/reject and by any direct integration that wants to record an outcome.

As of v3.7.7 the RL weight lives on the SOURCE STATION, not the product. This endpoint resolves mission → lead → station_id and adjusts stations.rl_weight: replied → +0.05 (clamped to 2.0) ignored → −0.02 (clamped to 0.5)

Legacy leads with station_id = NULL skip the rl_weight delta but still record into products.rejection_stats for analytics.

Idempotent (v3.7.7): re-recording an outcome on a mission that already has one is a silent no-op. /actions/approve now fires replied inline on every approval, so when the v1.5.x plugin calls /feedback/record as a follow-up, this endpoint sees the outcome already set and returns the existing weight unchanged.