redesigned payment page + a lot of fixes

frontend/pweb/lib/controllers/payments/page_ui.dart

@@ -0,0 +1,43 @@
+import 'package:flutter/widgets.dart';
+
+import 'package:pweb/models/state/visibility.dart';
+
+
+class PaymentPageUiController extends ChangeNotifier {
+  final TextEditingController searchController = TextEditingController();
+  final FocusNode searchFocusNode = FocusNode();
+
+  String _query = '';
+  VisibilityState _paymentDetailsVisibility = VisibilityState.hidden;
+
+  String get query => _query;
+  VisibilityState get paymentDetailsVisibility => _paymentDetailsVisibility;
+
+  void setQuery(String query) {
+    if (_query == query) return;
+    _query = query;
+    notifyListeners();
+  }
+
+  void clearSearch() {
+    if (searchController.text.isNotEmpty) {
+      searchController.clear();
+    }
+    searchFocusNode.unfocus();
+    setQuery('');
+  }
+
+  void togglePaymentDetails() {
+    _paymentDetailsVisibility = _paymentDetailsVisibility == VisibilityState.visible
+        ? VisibilityState.hidden
+        : VisibilityState.visible;
+    notifyListeners();
+  }
+
+  @override
+  void dispose() {
+    searchController.dispose();
+    searchFocusNode.dispose();
+    super.dispose();
+  }
+}