🧩 BSUID na pratica

CREATE TABLE contatos_whatsapp (
  business_id   UUID    NOT NULL,
  bsuid         TEXT    NOT NULL,
  phone_e164    TEXT,            -- opcional
  display_name  TEXT,
  username      TEXT,            -- @ se conhecido
  first_seen_at TIMESTAMPTZ,
  last_seen_at  TIMESTAMPTZ,
  PRIMARY KEY (business_id, bsuid)
);

CREATE TABLE mensagens_wa (
  id            UUID    PRIMARY KEY,
  business_id   UUID    NOT NULL,
  bsuid         TEXT    NOT NULL,
  message_id    TEXT    NOT NULL,
  direction     TEXT    NOT NULL, -- 'in' | 'out'
  body          JSONB,
  created_at    TIMESTAMPTZ,
  FOREIGN KEY (business_id, bsuid)
    REFERENCES contatos_whatsapp(business_id, bsuid),
  UNIQUE (business_id, message_id)
);