signOut

Sign out — biometric-gated. Clears the LOCAL sigil pointer and drops the cached SDK (MidnightSdkProvider.close), returning the panel to SigilStatus.None. Fully recoverable: the passkey stays in GPM, so the user signs back in (forge reuses it, or restore from cloud) to return to the SAME identity. The cloud backup is untouched. On biometric cancel or failure nothing changes — the sigil stays SigilStatus.Forged.