Release v2.17.3

Fixed

• Accepting an invitation no longer loops back to provider selection after a successful sign-in: the completion gate now accepts any session that was signed in while the invitation was pending — the person's deliberate choice for it — and only a session that predates the invitation is taken through provider selection. This repairs the regression 2.17.2 introduced for deployments where the challenge's capability binding does not survive the provider round trip.