Puffer Card v1.2.0

Added

• Optional icon next to the card title, or replacing it entirely
  (icon_mode: beside / replace), selectable via the visual editor's icon
  picker. The stub configuration now suggests a default tank icon.

Changed

• History chart curves are now smoothed using Catmull-Rom interpolation
  (converted to cubic Béziers), matching the look of popular history-graph
  cards instead of straight-segment lines.

Fixed

• The chart sensor multi-select could get out of sync with the rendered
  chart: on first enabling the chart, all configured sensors were drawn but
  none appeared selected in the editor: selecting one made the others
  disappear, and deselecting it left an empty chart area. chart_sensors is
  now always explicitly populated with all configured sensors as soon as the
  chart is enabled, so editor and rendering stay consistent from the start.