-- Research pipeline v2: topology_kind on the topic + a persisted outcome per
-- run so `reviewing`/`publishing`/`published` states have an artifact to
-- point at instead of the original prompt.
--
--   topology_kind — the graph shape start_topic builds when firing this
--     topic. Default 'hub_spoke' matches the prior implicit behavior.
--     Wizard exposes: hub_spoke, pipeline, hierarchical, star_moe. The
--     coordinator prompt in start_topic branches on this string.
--
--   research_outcomes — one row per run's final synthesis. Versioned per
--     topic (1, 2, …) so reject-with-revision loops keep history. body_md
--     is the coordinator's final_output verbatim; produced_by_run_id
--     back-links to the topology_runs row that made it (nullable + SET
--     NULL cascade so an old run being pruned doesn't drop the artifact).

ALTER TABLE research_topics
    ADD COLUMN topology_kind TEXT NOT NULL DEFAULT 'hub_spoke';

CREATE TABLE research_outcomes (
    id                 UUID PRIMARY KEY,
    topic_id           UUID NOT NULL REFERENCES research_topics (id) ON DELETE CASCADE,
    version            INTEGER NOT NULL,
    body_md            TEXT NOT NULL,
    produced_by_run_id UUID REFERENCES topology_runs (id) ON DELETE SET NULL,
    created_at         TIMESTAMPTZ NOT NULL DEFAULT now(),
    UNIQUE (topic_id, version)
);
CREATE INDEX research_outcomes_topic_idx
    ON research_outcomes (topic_id, version DESC);