feat(stars): sync implement unified purchase flow

internal/rpc/payments_stars_rpc_test.go

@@ -42,6 +42,27 @@ func TestOnPaymentsGetStarsStatusGranted(t *testing.T) {
 	}
 }
 
+func TestOnPaymentsGetStarsSubscriptionsReturnsTerminalEmptyPage(t *testing.T) {
+	r := starsRouter(t, 1000)
+	ctx := WithUserID(context.Background(), 1000000001)
+	status, err := r.onPaymentsGetStarsSubscriptions(ctx, &tg.PaymentsGetStarsSubscriptionsRequest{
+		Peer: &tg.InputPeerSelf{}, Offset: "",
+	})
+	if err != nil {
+		t.Fatalf("getStarsSubscriptions: %v", err)
+	}
+	amount, ok := status.Balance.(*tg.StarsAmount)
+	if !ok || amount.Amount != 1000 {
+		t.Fatalf("balance = %#v, want StarsAmount 1000", status.Balance)
+	}
+	if subscriptions, ok := status.GetSubscriptions(); ok || len(subscriptions) != 0 {
+		t.Fatalf("subscriptions = %+v ok=%v, want absent terminal page", subscriptions, ok)
+	}
+	if _, ok := status.GetSubscriptionsNextOffset(); ok {
+		t.Fatal("empty subscription page unexpectedly has next offset")
+	}
+}
+
 // TON 余额未建模：返回 starsTonAmount 的合法响应（不崩客户端）。
 func TestOnPaymentsGetStarsStatusTon(t *testing.T) {
 	r := starsRouter(t, 1000)