[Enhancement] Use accent color to highlight selected folder #338
Description
Issue/Description:
When a folder is selected, the highlight uses a color very similar to the background with low opacity, making the selection barely visible. This is especially noticeable on the Library Home view.
Other COSMIC apps and applets already use the system accent color for navbar and selection highlights, which provides clear visual feedback and a consistent design language across the ecosystem.
Using the accent color here would improve accessibility, clarity, and visual consistency.
Current Behavior:
Expected Behavior:
The selected folder should be highlighted using the system accent color, similar to how navbar selections are implemented in other COSMIC apps and applets.
