Feat: add floating label to textarea (#7121)

## Summary

Adds the label/name of the widget as a floating label.

## Screenshots

<img width="543" height="469" alt="image"
src="https://github.com/user-attachments/assets/99d70e0b-f7b7-4b62-bf15-a2db8437c886"
/>


<!-- Add screenshots or video recording to help explain your changes -->

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-7121-Feat-add-floating-label-to-textarea-2be6d73d3650819c958efa893e0e304a)
by [Unito](https://www.unito.io)

---------

Co-authored-by: github-actions <github-actions@github.com>

src/renderer/extensions/vueNodes/widgets/components/WidgetTextarea.test.ts

@@ -179,8 +179,8 @@ describe('WidgetTextarea Value Binding', () => {
       const widget = createMockWidget('test')
       const wrapper = mountComponent(widget, 'test')
 
-      const textarea = wrapper.find('textarea')
-      expect(textarea.attributes('placeholder')).toBe('test_textarea')
+      const textareaLabel = wrapper.find('label')
+      expect(textareaLabel.text()).toBe('test_textarea')
     })
 
     it('uses provided placeholder when specified', () => {