fix: add BaseStrokeThickness property to IMapAnchorViewModel

This commit introduces property for the initial stroke thickness of map anchors: "BaseStrokeThickness." This property allows configuring visual appearance of map anchors for better fit and precision. It can be adjusted independently and will affect the rendering of the map anchors on the map.

Asana: https://app.asana.com/0/1203851531040615/1207177984234823/f

src/Asv.Avalonia.Map/ViewModels/MapAnchorViewModel.cs

@@ -185,10 +185,14 @@ public interface IMapAnchorViewModel
         /// The size of the object.
         /// </value>
         double Size { get; set; }
-        
+
         /// <summary>
-        /// 
+        /// Represents the base size of a map anchor on the map.
         /// </summary>
+        /// <remarks>
+        /// This property determines the initial size of the map anchor when it is rendered on the map.
+        /// The size is measured in units and can be adjusted to fit the desired visual appearance.
+        /// </remarks>
         double BaseSize { get; set; }
 
         /// <summary>
@@ -227,6 +231,14 @@ public interface IMapAnchorViewModel
         /// </value>
         IBrush Stroke { get; set; }
 
+        /// <summary>
+        /// The base thickness of the stroke for the map anchor.
+        /// </summary>
+        /// <remarks>
+        /// This property determines the base thickness of the stroke for the map anchor. The stroke thickness can be modified using the <see cref="StrokeThickness"/> property, which takes into account the base stroke thickness.
+        /// </remarks>
+        double BaseStrokeThickness { get; set; }
+
         /// property `StrokeThickness` in C#
         double StrokeThickness { get; set; }