controller v0.264.0: the household is told when an update is undone or held, in its language

app_update_undone / app_update_held events (09 decision 15), on by
default and seeded once on existing boxes; R-606 update sentences as
key+args rendered per reader; R-646 startup applied-meta backfill for
apps current with the catalog; R-620 a disabled notifier WARNs once per
event type. Needs hub v0.120.0.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0159rPz1ZhFKsS53msqPYxtS

controller/internal/settings/app_update_seed_test.go

@@ -0,0 +1,48 @@
+package settings
+
+import (
+	"io"
+	"log"
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+// v0.264.0 — the one-time, ADD-ONLY seed of the two update event types into a household's stored prefs.
+//
+// COMPANION RED-PROOF (REPORT.md): drop the seedAppUpdateEvents call from Load — the first assertion fails.
+func TestSeedAppUpdateEvents_AddOnlyOnce(t *testing.T) {
+	p := filepath.Join(t.TempDir(), "settings.json")
+	if err := os.WriteFile(p, []byte(`{"notifications":{"email":"h@example.hu","enabled_events":["backup_failed"]}}`), 0o600); err != nil {
+		t.Fatal(err)
+	}
+	lg := log.New(io.Discard, "", 0)
+	s, err := Load(p, lg)
+	if err != nil {
+		t.Fatal(err)
+	}
+	ev := s.Notifications.EnabledEvents
+	has := func(list []string, x string) bool {
+		for _, e := range list {
+			if e == x {
+				return true
+			}
+		}
+		return false
+	}
+	if !has(ev, "backup_failed") || !has(ev, "app_update_undone") || !has(ev, "app_update_held") {
+		t.Fatalf("the household's choice must be kept and both types added, got %v", ev)
+	}
+	// The household opts out of one; a restart must NOT add it back.
+	s.Notifications.EnabledEvents = []string{"backup_failed", "app_update_held"}
+	if err := s.save(); err != nil {
+		t.Fatal(err)
+	}
+	s2, err := Load(p, lg)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if has(s2.Notifications.EnabledEvents, "app_update_undone") {
+		t.Errorf("a later opt-out must stick — the seed runs once, got %v", s2.Notifications.EnabledEvents)
+	}
+}