AbstractContinuum 0.7.5

• Fixed (QA item (11)): a fresh install without a hub seat key showed raw 503s (hub_seat_unavailable) because the
  Board's live claims, a card's hub activity and the Team page fired hub calls before reading api/hub/meta. They read
  it first; unconfigured, they fire no hub route (and the Team page opens no socket) and say "The team hub is not
  configured." with the proxy's sentence on how to configure it (api/hub/meta now carries setup); the Desk tab says
  the same. A key added later is picked up without a reload (Team re-reads meta every 15 s and when the tab comes back;
  the Board at its 30 s tick). Tests: src/ui/board/hub_not_configured.test.tsx (5) and two Team page pins; each red
  without its check. Adversarial review (Opus): the not-configured state never re-checked, the Desk tab still fired,
  the card-activity gate was untested: fixed.