refactor(core): move clamps into OpenNest.Clamps

Co-Authored-By: Claude Fable 5.2 <noreply@anthropic.com>

OpenNest.IO/NestFormat.cs

@@ -424,12 +424,12 @@ namespace OpenNest.IO
 
             /// <summary>
             /// Minutes to remove one clamp and put it back after cutting (D9). Null in older
-            /// files and readers fall back to <see cref="OpenNest.ClampRail.DefaultRemovalMinutes"/>.
+            /// files and readers fall back to <see cref="OpenNest.Clamps.ClampRail.DefaultRemovalMinutes"/>.
             /// </summary>
             public double? RemovalMinutes { get; init; }
 
             /// <summary>
-            /// The gap parts keep from every clamp (<see cref="OpenNest.ClampRail.Clearance"/>).
+            /// The gap parts keep from every clamp (<see cref="OpenNest.Clamps.ClampRail.Clearance"/>).
             /// Omitted when the rail uses the sheet's bottom edge spacing, as older files do.
             /// </summary>
             public double? Clearance { get; init; }

OpenNest.IO/NestReader.cs

@@ -9,6 +9,7 @@ using System.Text.Json.Nodes;
 using OpenNest.Bending;
 using OpenNest.BestFit;
 using OpenNest.Breakoffs;
+using OpenNest.Clamps;
 using OpenNest.CNC;
 using OpenNest.CNC.CuttingStrategy;
 using OpenNest.Converters;

OpenNest.IO/NestWriter.cs

@@ -8,6 +8,7 @@ using System.Security.Cryptography;
 using System.Text;
 using System.Text.Json;
 using OpenNest.BestFit;
+using OpenNest.Clamps;
 using OpenNest.CNC;
 using OpenNest.Support;
 using static OpenNest.IO.NestFormat;