LockdownModeSetting
Runtime lockdown-mode toggle for the security settings screen.
The switch and its dialogs are driven entirely by the latest lockdownState:
LockdownState.Disabled / LockdownState.NeedsProvision → OFF; turning ON opens the set-passphrase dialog with the one-time irreversible warning.
LockdownState.Locked → ON (locked); authentication is handled by the global lockdown dialog, so the switch is read-only here.
LockdownState.AwaitingResponse → temporarily non-actionable after transport admission while firmware processes a lockdown command.
LockdownState.Unlocked → ON; turning OFF opens the disable dialog, plus a "Lock now" affordance and session info.
Visibility is gated on supported — the firmware-version capability from Capabilities.supportsLockdown (lockdown ships in firmware v2.8.0). lockdownState drives the switch position once a LockdownStatus arrives.