feat(derivatives): fix Trade Republic derivative pagination streaming and picker modal

FinlyticApp/lib/core/theme/custom_scroll_behavior.dart

@@ -0,0 +1,16 @@
+import 'package:flutter/gestures.dart';
+import 'package:flutter/material.dart';
+
+/// Global scroll behavior enabling smooth mouse dragging, mouse wheel, and touch scrolling
+/// across all platforms (especially Flutter Web on Desktop without requiring Shift-key).
+class CustomAppScrollBehavior extends MaterialScrollBehavior {
+  const CustomAppScrollBehavior();
+
+  @override
+  Set<PointerDeviceKind> get dragDevices => {
+        PointerDeviceKind.touch,
+        PointerDeviceKind.mouse,
+        PointerDeviceKind.stylus,
+        PointerDeviceKind.trackpad,
+      };
+}