Replace the prep-lane stub with the real Flow C: a fullscreen,
undecorated adw::ApplicationWindow that queries the daemon's pending
flag for the current user, presents an AdwStatusPage "Get started"
button when a flag is set, runs the Phase 8 enrollment dialog, calls
ClearPendingFlag on success, and exits. A 60s idle watchdog (5s tick)
falls back to gnome-session-quit --logout. EventControllerKey and
GestureClick poke the WatchdogState on activity; missing pending flag
short-circuits to immediate exit so the autostart cost is one D-Bus
call.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Convert gui/src/firstrun.rs to a module dir with watchdog.rs, the
pure-logic WatchdogState helper that the GTK widget code in Task 2
will poll. Three unit tests cover fresh/expired/poke transitions.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
