added comment for payment, changed intent and added amount ui in operations

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

@@ -0,0 +1,53 @@
+import 'package:flutter/material.dart';
+
+import 'package:pshared/provider/payment/amount.dart';
+
+
+class PaymentCommentFieldController extends ChangeNotifier {
+  final TextEditingController textController;
+
+  PaymentAmountProvider? _provider;
+  bool _isSyncingText = false;
+
+  PaymentCommentFieldController({required String initialComment})
+    : textController = TextEditingController(text: initialComment);
+
+  void update(PaymentAmountProvider provider) {
+    if (identical(_provider, provider)) {
+      _syncTextWithComment(provider.comment);
+      return;
+    }
+    _provider?.removeListener(_handleProviderChanged);
+    _provider = provider;
+    _provider?.addListener(_handleProviderChanged);
+    _syncTextWithComment(provider.comment);
+  }
+
+  void handleChanged(String value) {
+    if (_isSyncingText) return;
+    _provider?.setComment(value);
+  }
+
+  void _handleProviderChanged() {
+    final provider = _provider;
+    if (provider == null) return;
+    _syncTextWithComment(provider.comment);
+  }
+
+  void _syncTextWithComment(String comment) {
+    if (textController.text == comment) return;
+    _isSyncingText = true;
+    textController.value = TextEditingValue(
+      text: comment,
+      selection: TextSelection.collapsed(offset: comment.length),
+    );
+    _isSyncingText = false;
+  }
+
+  @override
+  void dispose() {
+    _provider?.removeListener(_handleProviderChanged);
+    textController.dispose();
+    super.dispose();
+  }
+}