Move converters to OpenNest.Converters namespace

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

OpenNest.Core/Converters/ConvertMode.cs

@@ -0,0 +1,53 @@
+using OpenNest.CNC;
+using OpenNest.Geometry;
+
+namespace OpenNest.Converters
+{
+    public static class ConvertMode
+    {
+        /// <summary>
+        /// Converts the program to absolute coordinates.
+        /// Does NOT check program mode before converting.
+        /// </summary>
+        /// <param name="pgm"></param>
+        public static void ToAbsolute(Program pgm)
+        {
+            var pos = new Vector(0, 0);
+
+            for (int i = 0; i < pgm.Codes.Count; ++i)
+            {
+                var code = pgm.Codes[i];
+                var motion = code as Motion;
+
+                if (motion != null)
+                {
+                    motion.Offset(pos);
+                    pos = motion.EndPoint;
+                }
+            }
+        }
+
+        /// <summary>
+        /// Converts the program to intermental coordinates.
+        /// Does NOT check program mode before converting.
+        /// </summary>
+        /// <param name="pgm"></param>
+        public static void ToIncremental(Program pgm)
+        {
+            var pos = new Vector(0, 0);
+
+            for (int i = 0; i < pgm.Codes.Count; ++i)
+            {
+                var code = pgm.Codes[i];
+                var motion = code as Motion;
+
+                if (motion != null)
+                {
+                    var pos2 = motion.EndPoint;
+                    motion.Offset(-pos.X, -pos.Y);
+                    pos = pos2;
+                }
+            }
+        }
+    }
+}