style: apply CSharpier formatting to all C# sources

Repo-wide sweep with the pinned CSharpier 1.3.0 tool. Whitespace and
line-wrapping only; OpenNest.Engine.Tests (109) and OpenNest.IO.Tests
pass after reformat, full solution builds 0 errors.

Added .csharpierignore so csproj/config XML keeps its existing layout
(CSharpier's XML wrapping churns attributes with zero benefit).

Formatting is now enforceable: dotnet csharpier check . passes.

OpenNest.Data/LocalJsonProvider.cs

@@ -11,7 +11,7 @@ public class LocalJsonProvider : IDataProvider
     {
         WriteIndented = true,
         PropertyNamingPolicy = JsonNamingPolicy.CamelCase,
-        Converters = { new JsonStringEnumConverter(JsonNamingPolicy.CamelCase) }
+        Converters = { new JsonStringEnumConverter(JsonNamingPolicy.CamelCase) },
     };
 
     public LocalJsonProvider(string directory)
@@ -77,19 +77,23 @@ public class LocalJsonProvider : IDataProvider
             return;
 
         var assembly = typeof(LocalJsonProvider).Assembly;
-        var resourceName = assembly.GetManifestResourceNames()
+        var resourceName = assembly
+            .GetManifestResourceNames()
             .FirstOrDefault(n => n.EndsWith("CL-980.json"));
 
-        if (resourceName is null) return;
+        if (resourceName is null)
+            return;
 
         using var stream = assembly.GetManifestResourceStream(resourceName);
-        if (stream is null) return;
+        if (stream is null)
+            return;
 
         using var reader = new StreamReader(stream);
         var json = reader.ReadToEnd();
 
         var config = JsonSerializer.Deserialize<MachineConfig>(json, JsonOptions);
-        if (config is null) return;
+        if (config is null)
+            return;
 
         SaveMachine(config);
     }

OpenNest.Data/MachineConfig.cs

@@ -14,13 +14,15 @@ public class MachineConfig
     public ThicknessConfig? GetParameters(string material, double thickness)
     {
         var mat = GetMaterial(material);
-        if (mat is null) return null;
+        if (mat is null)
+            return null;
         return mat.Thicknesses.FirstOrDefault(t => t.Value.IsEqualTo(thickness));
     }
 
     public MaterialConfig? GetMaterial(string name)
     {
         return Materials.FirstOrDefault(m =>
-            string.Equals(m.Name, name, StringComparison.OrdinalIgnoreCase));
+            string.Equals(m.Name, name, StringComparison.OrdinalIgnoreCase)
+        );
     }
 }

OpenNest.Data/MachineType.cs

@@ -4,5 +4,5 @@ public enum MachineType
 {
     Laser,
     Plasma,
-    Waterjet
+    Waterjet,
 }

OpenNest.Data/UnitSystem.cs

@@ -3,5 +3,5 @@ namespace OpenNest.Data;
 public enum UnitSystem
 {
     Inches,
-    Millimeters
+    Millimeters,
 }