Add File Dialog Support to Drop Zone in Attachments Section

[trycoast]

Currently, the attachments section features a drop zone for file uploads. I would like to request the addition of file dialog support when clicking on the drop zone. This enhancement would improve user experience by allowing files to be selected via the file dialog in addition to drag-and-drop. It might be beneficial to add button effects to the placeholder component to indicate this functionality.

Steps to Implement:

1. Modify the drop zone to open the file dialog on click.
2. Add visual feedback (e.g., button effects) to the placeholder component to signal clickable functionality.

Benefit:

This feature would make the file upload process more intuitive and accessible for users who prefer using the file dialog over drag-and-drop.