CREATE TABLE IF NOT EXISTS milestone_achievements (
  id           UUID PRIMARY KEY DEFAULT gen_random_uuid(),
  child_id     UUID NOT NULL REFERENCES children(id) ON DELETE CASCADE,
  family_id    UUID NOT NULL,
  milestone_key TEXT NOT NULL,
  achieved_at  DATE NOT NULL,
  notes        TEXT,
  created_at   TIMESTAMPTZ NOT NULL DEFAULT now(),
  UNIQUE(child_id, milestone_key)
);
CREATE INDEX IF NOT EXISTS milestone_child_idx ON milestone_achievements (child_id);