Switch all echarts-based chart imports to the dedicated core-ui charts
entry so echarts stays out of the synchronous entry bundle and loads
only on chart routes. Requires @gpustack/core-ui with the ./charts export.
- bar-chart: barMinWidth so hour-granularity bars stay visible with gaps.
- pie-chart: single legend-beside-pie layout, value (percent%) tooltip,
2-decimal rounding for the Summary donut.