Demonstrate MarkerSize in existing WinDataChart hoodie samples

[Copilot]

This update adds a focused demo of the new chart MarkerSize property in the existing hoodie sales chart samples. It keeps the current sample structure and highlights marker sizing on the selected series while preserving default template sizing for non-selected series.

• Scope

  • Updated the two mirrored sample implementations:
    • Applications/Elemental/Elemental/frmMain.cs
    • Applications/IGExcel/IGExcel/ofrmMain.cs

• Chart marker sizing behavior

  • In InitializeChart(HoodieStyle style), each LineSeries now sets MarkerSize explicitly:
    • selected series: fixed marker size (18D)
    • non-selected series: reset to default marker sizing (double.NaN)

• Result

  • The sample now visibly demonstrates the new MarkerSize API in a real chart configuration without introducing new sample projects or restructuring existing flow.

series.Thickness = isSelected ? 4D : 2D;
series.MarkerType = isSelected ? MarkerType.Circle : MarkerType.None;
series.MarkerSize = isSelected ? 18D : double.NaN;
series.MarkerBrush = barColor;
series.MarkerOutline = barColor;