-- F-08 durable conversation history: replaces RagAgent's in-process dict
-- (lost on restart, not shared across workers). Append-only; `id`'s
-- insertion order is the "oldest -> newest" ordering the understanding LLM
-- prompt already expects, no separate turn-index column needed.
CREATE TABLE IF NOT EXISTS rag_conversation_turn (
    id bigserial PRIMARY KEY,
    conversation_id text NOT NULL,
    line text NOT NULL,
    created_at timestamptz NOT NULL DEFAULT now()
);

CREATE INDEX IF NOT EXISTS rag_conversation_turn_conv_idx
    ON rag_conversation_turn (conversation_id, id);