[Feature]: Use album cover as folder icon

[kozabr]

Is your feature request related to a problem?

In folder view, all folders currently display a generic folder icon.

Describe the solution you'd like

• Display the album cover (from embedded tag or folder image file, e.g. cover.jpg) as the folder thumbnail.
• If multiple albums exist in one folder, use the first track’s cover or a collage.
  Benefit:
  Improves visual experience, makes navigation easier, and helps users quickly identify albums by artwork instead of folder names.

Describe alternatives you've considered

No response