Implemented CSS styles for an optimal fee indicator, including a gold star and a label. Updated HTML to conditionally show the star and "DATUM" label when the pool fees percentage is between 0.9 and 1.3.
Updated `MiningDashboardService` to calculate and display
the `pool_fees_percentage` metric, reflecting earnings lost
to pool fees. Enhanced error handling for earnings processing.
Updated styles in `dashboard.css` for the new metric and
added corresponding HTML elements in `dashboard.html` to
ensure proper display and conditional rendering.
