-- B06案例版本只追加，当前指针由S01作者操作推进。
CREATE TABLE public.muse_quality_case (
    case_id uuid PRIMARY KEY,
    author_id text NOT NULL,
    current_revision bigint NOT NULL CHECK(current_revision>0)
);
CREATE TABLE public.muse_quality_case_version (
    case_id uuid NOT NULL REFERENCES public.muse_quality_case(case_id),
    revision bigint NOT NULL CHECK(revision>0),
    state text NOT NULL CHECK(state IN ('shadow','confirmed','withdrawn')),
    payload jsonb NOT NULL CHECK(jsonb_typeof(payload)='object'),
    payload_hash text NOT NULL CHECK(payload_hash ~ '^[0-9a-f]{64}$'),
    created_at timestamptz NOT NULL DEFAULT clock_timestamp(),
    PRIMARY KEY(case_id,revision)
);
ALTER TABLE public.muse_quality_case ADD CONSTRAINT quality_case_current_fk
    FOREIGN KEY(case_id,current_revision) REFERENCES public.muse_quality_case_version(case_id,revision)
    DEFERRABLE INITIALLY DEFERRED;
CREATE TRIGGER quality_case_history_guard BEFORE UPDATE OR DELETE ON public.muse_quality_case_version
    FOR EACH ROW EXECUTE FUNCTION public.muse_guard_literary_history();