Host power-off for the household (R-998): POST /host/poweroff

The guest's controller asks; the agent refuses in the first 10 min after boot, a second time in
one boot (persisted, keyed by /proc/stat btime), and while a backup, restore test, OS step,
controller update, drive format, NAS verify, escrow ceremony or vzdump runs (each a named 409
reason). On acceptance: the record first, a host report carrying deliberate_off accepted by the
hub (bounded 60 s), then pct shutdown --timeout 120, then systemctl poweroff.

Sudoers: two exact vectors (pct ^shutdown N --timeout N$, systemctl poweroff) in FELHOM_POWEROFF;
nine injection cases. New TestEveryAliasIsGranted: a defined alias missing from the grant line
passed the coverage check before. Every new test red-proofed.

internal/localapi/server.go

@@ -394,6 +394,10 @@ type Server struct {
 	// detached pipeline runs through (tests inject; production defaults set in NewServer).
 	netVerifyMu  sync.Mutex
 	netVerifyCur *netVerifyJob
+
+	// R-998: POST /host/poweroff (nil = not configured → 503); one guard-and-mark decision at a time.
+	powerOff   *HostPowerOffConfig
+	powerOffMu sync.Mutex
 	// netTrigger performs the mount-waking directory read through the automount path (Q1).
 	netTrigger func(where string) error
 	// netMounted judges mount success from /proc/mounts — the §8 truth source (never readability).
@@ -550,6 +554,8 @@ func (s *Server) Handler() http.Handler {
 	mux.HandleFunc("POST /disks/guest-attach", s.withGuest(s.handleDiskGuestAttach))
 	// Guest reboot (slice 10 P2 activation): user-triggered restart to activate pending drive binds.
 	mux.HandleFunc("POST /guest/reboot", s.withGuest(s.handleGuestReboot))
+	// Host power-off (R-998, doc 14): the household's „A gép kikapcsolása". Guarded in hostpoweroff.go.
+	mux.HandleFunc("POST /host/poweroff", s.withGuest(s.handleHostPowerOff))
 	// Guest RAM resize (v0.90.0, R-24): read current allocation + bounds, and apply a bounded resize
 	// (live cgroup apply, no reboot). Self-scoped; the agent enforces every bound fresh per request.
 	mux.HandleFunc("GET /guest/memory", s.withGuest(s.handleGuestMemory))