
List active trait aggregation rules
list_trait_aggregations.RdReturns one row per rule with both `source_trait_id` / `source_trait` and `target_trait_id` / `target_trait`. When `target_trait_id` is NULL in the config (meaning "same as source"), the returned `effective_target_trait_id` is filled with `source_trait_id` to make downstream filtering trivial.