fix(delete): review follow-ups — admin Deleted filter, guest gate, dialog spacing

- Admin /users gains a Deleted scope (between People and Robots); every other scope now
  hides tombstoned accounts (deleted_at filter in UserFilter).
- Admin delete-user is offered for any non-deleted account (drop the not-guest gate, so a
  stale is_guest account can still be tombstoned).
- Harden EmailService.ConfirmCode to ClearGuest — defence-in-depth so no confirmed-email
  path leaves is_guest set (the currently-live paths already do).
- Space the delete/change dialog's action row from its input field.
Integration tests: the Deleted filter scoping + ConfirmCode guest promotion.

backend/internal/inttest/delete_test.go

@@ -134,6 +134,85 @@ func TestDeletionDossierReaders(t *testing.T) {
 	}
 }
 
+// listHasID reports whether the user list contains accountID.
+func listHasID(items []account.UserListItem, id uuid.UUID) bool {
+	for _, it := range items {
+		if it.ID == id {
+			return true
+		}
+	}
+	return false
+}
+
+// TestUserListDeletedFilter: a tombstoned account is hidden from the default People list and
+// shown only under the Deleted scope.
+func TestUserListDeletedFilter(t *testing.T) {
+	ctx := context.Background()
+	store := account.NewStore(testDB)
+	deleter := accountdelete.NewDeleter(testDB)
+
+	live, _, err := store.ProvisionTelegram(ctx, "tg-"+uuid.NewString(), "en", "", "Live", "")
+	if err != nil {
+		t.Fatalf("provision live: %v", err)
+	}
+	gone, _, err := store.ProvisionTelegram(ctx, "tg-"+uuid.NewString(), "en", "", "Gone", "")
+	if err != nil {
+		t.Fatalf("provision gone: %v", err)
+	}
+	if err := deleter.AnonymizeAndTombstone(ctx, gone.ID); err != nil {
+		t.Fatalf("delete: %v", err)
+	}
+
+	people, err := store.ListUsers(ctx, account.UserFilter{}, 5000, 0)
+	if err != nil {
+		t.Fatalf("list people: %v", err)
+	}
+	if listHasID(people, gone.ID) {
+		t.Error("a deleted account must not appear in the default People list")
+	}
+	if !listHasID(people, live.ID) {
+		t.Error("a live account must appear in the default People list")
+	}
+	deleted, err := store.ListUsers(ctx, account.UserFilter{Deleted: true}, 5000, 0)
+	if err != nil {
+		t.Fatalf("list deleted: %v", err)
+	}
+	if !listHasID(deleted, gone.ID) {
+		t.Error("a deleted account must appear in the Deleted list")
+	}
+	if listHasID(deleted, live.ID) {
+		t.Error("a live account must not appear in the Deleted list")
+	}
+}
+
+// TestConfirmCodeClearsGuest: confirming an email on a guest via ConfirmCode promotes it to
+// a durable account (defence-in-depth — no confirmed-email path leaves is_guest set).
+func TestConfirmCodeClearsGuest(t *testing.T) {
+	ctx := context.Background()
+	store := account.NewStore(testDB)
+	mailer := &capturingMailer{}
+	svc := account.NewEmailService(store, mailer, "https://erudit-game.ru")
+
+	guest, err := store.ProvisionGuest(ctx, "")
+	if err != nil {
+		t.Fatalf("provision guest: %v", err)
+	}
+	email := "cc-" + uuid.NewString() + "@example.com"
+	if err := svc.RequestCode(ctx, guest.ID, email); err != nil {
+		t.Fatalf("request code: %v", err)
+	}
+	if _, err := svc.ConfirmCode(ctx, guest.ID, email, sixDigit.FindString(mailer.lastBody)); err != nil {
+		t.Fatalf("confirm code: %v", err)
+	}
+	after, err := store.GetByID(ctx, guest.ID)
+	if err != nil {
+		t.Fatalf("load: %v", err)
+	}
+	if after.IsGuest {
+		t.Error("confirming an email must clear the guest flag")
+	}
+}
+
 // TestDropAllRobotGames drops the deletee's solo vs-AI game but keeps a game with a human
 // opponent.
 func TestDropAllRobotGames(t *testing.T) {