feat(tree): add flat and lazy modes for tree data handling

* Implement flat mode to transform flat data with parentId to nested structure.
* Introduce lazy mode for on-demand loading of children.
* Update tree rendering logic to accommodate new modes.
* Enhance tree cell expansion logic to support lazy loading.
* Add dark mode styles for improved UI experience.
* Create comprehensive end-to-end tests for tree functionality.

.storybook/preview.ts

@@ -4,6 +4,23 @@ import { PreviewDecorator } from './previewDecorator';
 
 const preview: Preview = {
   decorators: [PreviewDecorator],
+  globalTypes: {
+    colorScheme: {
+      description: 'Mantine color scheme',
+      toolbar: {
+        dynamicTitle: true,
+        icon: 'paintbrush',
+        items: [
+          { icon: 'sun', title: 'Light', value: 'light' },
+          { icon: 'moon', title: 'Dark', value: 'dark' },
+        ],
+        title: 'Color Scheme',
+      },
+    },
+  },
+  initialGlobals: {
+    colorScheme: 'light',
+  },
   parameters: {
     actions: { argTypesRegex: '^on[A-Z].*' },
     controls: {