Settings and Export

User story

I want an easy way to export my grid design for sharing or future usage.

Acceptance criteria

• A settings icon is available with a hover tooltip and a selected state.
• Clicking on the settings icon opens a popup with an export-to-JSON option.
• Users can rename the export file before downloading.
• The download button is disabled if the filename is empty.
• The JSON file should map the grid as a 2D array with asset index values.