Change icon view to grid and display details in a popup

### Problem

Currently, the application displays icons in a horizontal list within a split view:

- Category panel: shows the list of available categories.
- Icon panel: displays a row of icons based on the selected category.
- Detail panel: shows icon information when an icon is selected.

While this layout works, the row-based list limits the number of visible icons, making visual browsing slower and less intuitive.

### Proposal

**Proposed change:**
- Grid view: Change the icon panel to a grid view to display more icons simultaneously, improving visual exploration.
- Popup for details: Instead of a fixed detail panel, display icon details in a popup when an icon is selected. This allows for more space to browse icons without losing context.

**Benefits**:
- Enhances user experience by displaying more icons at once.
- Makes visual searching more efficient and less tedious.
- The detail popup provides a more dynamic experience without overloading the main interface.

### Prior Art (Optional)

_No response_