test(sweep): add capture surfaces for the Wave-1 standalone modals

Register sweep surfaces so the redesigned Wave-1 modals get captured for visual
review: modal-qr-popup, modal-request-payment, modal-validate-address,
modal-address-label, modal-daemon-prompt, and modal-antivirus (the last renders
only on Windows, where its #ifdef body compiles). Each is driven through the
dialog's public show()/flag; teardown closes it. Adds a static hide() to
RequestPaymentDialog / ValidateAddressDialog / AddressLabelDialog for clean sweep
teardown (they had no public close). The contact add/edit and explorer block-detail
modals are tab-embedded and not yet surfaced.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/ui/windows/request_payment_dialog.cpp

@@ -59,6 +59,15 @@ void RequestPaymentDialog::show(const std::string& address)
     }
 }
 
+void RequestPaymentDialog::hide()
+{
+    s_open = false;
+    if (s_qr_texture != 0) {
+        FreeQRTexture(s_qr_texture);
+        s_qr_texture = 0;
+    }
+}
+
 void RequestPaymentDialog::render(App* app)
 {
     if (!s_open) return;