- JSON field predicates and value facets
- landed-at and broker timestamp ranges
- partition and offset ranges
- stable preview columns
- cursor pagination
- full-record inspection up to 16 MiB
raw__<source> landing history. They do not query Kafka, change a consumer
group, or alter the source. Broker inventory, consumer lag, and retained-message queries remain
separate operations so one unavailable signal does not disable the others.

Retained-message visibility is bounded by the source landing TTL. The browser cannot recover data
that ClickHouse has already expired.

