refactor(desktop): sort paged server lists from the header in BrowsePager

The drawing library, drawing sets, saved nests, add-release and edit-set
grids each repeated the left-click header check that sorts on the
server. BrowsePager.SortByHeaderAsync now does it for the grid and
session it already drives. No behavior change.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

OpenNest.WinForms.Tests/Controls/BrowsePagerTests.cs

@@ -0,0 +1,135 @@
+using System.Threading;
+using System.Threading.Tasks;
+using System.Windows.Forms;
+using OpenNest.Controls;
+using OpenNest.Data;
+
+namespace OpenNest.WinForms.Tests.Controls;
+
+public class BrowsePagerTests
+{
+    private enum Field { Name, Size }
+
+    private enum OtherField { Size }
+
+    [Fact]
+    public void LeftClickOnASortColumnSortsOnTheServerAndReversesOnTheSameColumn() => RunSta(() =>
+    {
+        using var host = new Host();
+
+        host.Click(host.SizeColumn, MouseButtons.Left);
+
+        Assert.Equal(1, host.Session.Queries);
+        Assert.Equal(Field.Size, host.Session.Sort);
+        Assert.False(host.Session.Descending);
+        Assert.Equal(1, host.Populated);
+
+        host.Click(host.SizeColumn, MouseButtons.Left);
+
+        Assert.Equal(2, host.Session.Queries);
+        Assert.True(host.Session.Descending);
+    });
+
+    [Fact]
+    public void OtherButtonsDoNotSort() => RunSta(() =>
+    {
+        using var host = new Host();
+
+        host.Click(host.SizeColumn, MouseButtons.Right);
+        host.Click(host.SizeColumn, MouseButtons.Middle);
+
+        Assert.Equal(0, host.Session.Queries);
+        Assert.Equal(Field.Name, host.Session.Sort);
+    });
+
+    [Fact]
+    public void ColumnsWithoutThisListsSortFieldDoNotSort() => RunSta(() =>
+    {
+        using var host = new Host();
+
+        host.Click(host.UntaggedColumn, MouseButtons.Left);
+        host.Click(host.ForeignColumn, MouseButtons.Left);
+
+        Assert.Equal(0, host.Session.Queries);
+        Assert.Equal(Field.Name, host.Session.Sort);
+    });
+
+    private static void RunSta(Action action) =>
+        StaTestThread.Run(action, TimeSpan.FromSeconds(30), "The STA test did not complete.");
+
+    private sealed class Host : IDisposable
+    {
+        private readonly DataGridView grid = new();
+        private readonly Label summary = new();
+        private readonly Button previous = new();
+        private readonly Button next = new();
+        private readonly BrowsePager<Page, Field> pager;
+
+        public Host()
+        {
+            UntaggedColumn = grid.Columns.Add("untagged", "Untagged");
+            SizeColumn = grid.Columns.Add("size", "Size");
+            ForeignColumn = grid.Columns.Add("foreign", "Foreign");
+            grid.Columns[SizeColumn].Tag = Field.Size;
+            grid.Columns[ForeignColumn].Tag = OtherField.Size;
+            pager = new BrowsePager<Page, Field>(
+                Session, grid, summary, previous, next, "the test list")
+            {
+                Populate = _ => Populated++,
+            };
+        }
+
+        public TestSession Session { get; } = new();
+
+        public int UntaggedColumn { get; }
+
+        public int SizeColumn { get; }
+
+        public int ForeignColumn { get; }
+
+        public int Populated { get; private set; }
+
+        public void Click(int column, MouseButtons button)
+        {
+            var mouse = new MouseEventArgs(button, 1, 0, 0, 0);
+            pager.SortByHeaderAsync(new DataGridViewCellMouseEventArgs(column, -1, 0, 0, mouse))
+                .GetAwaiter().GetResult();
+        }
+
+        public void Dispose()
+        {
+            Session.Dispose();
+            grid.Dispose();
+            summary.Dispose();
+            previous.Dispose();
+            next.Dispose();
+        }
+    }
+
+    private sealed class Page : IBrowsePage
+    {
+        public int Offset => 0;
+
+        public int Total => 0;
+
+        public int ItemCount => 0;
+    }
+
+    private sealed class TestSession : BrowseSession<Page, Field>
+    {
+        public TestSession()
+            : base(pageSize: 10, maxPageSize: 100, Field.Name)
+        {
+        }
+
+        public int Queries { get; private set; }
+
+        public override string Summary => "";
+
+        protected override Task<Page> QueryAsync(CancellationToken cancellationToken)
+        {
+            Queries++;
+            return Task.FromResult(new Page());
+        }
+    }
+}

OpenNest/Controls/BrowsePager.cs

@@ -84,6 +84,15 @@ namespace OpenNest.Controls
             }
         }
 
+        /// <summary>
+        /// Sorts by a left-clicked column whose <see cref="DataGridViewColumn.Tag"/> is a sort
+        /// field. Sorting a page locally would misrepresent the list; the server sorts all matches.
+        /// </summary>
+        public Task SortByHeaderAsync(DataGridViewCellMouseEventArgs e) =>
+            e.Button == MouseButtons.Left && grid.Columns[e.ColumnIndex].Tag is TSort field
+                ? RunAsync(() => session.SortByAsync(field))
+                : Task.CompletedTask;
+
         public void UpdateNavigation()
         {
             previous.Enabled = !session.IsLoading && session.CanGoPrevious;

OpenNest/Controls/DrawingLibraryView.cs

@@ -216,12 +216,9 @@ namespace OpenNest.Controls
             await RunAsync(() => session.SetShowAllAsync(showAll));
         }
 
-        private async void DrawingGrid_ColumnHeaderMouseClick(object sender, DataGridViewCellMouseEventArgs e)
-        {
-            // Sorting a page locally would misrepresent the library; the server sorts all matches.
-            if (e.Button == MouseButtons.Left && drawingGrid.Columns[e.ColumnIndex].Tag is DrawingSortField field)
-                await RunAsync(() => session.SortByAsync(field));
-        }
+        private async void DrawingGrid_ColumnHeaderMouseClick(
+            object sender, DataGridViewCellMouseEventArgs e) =>
+            await pager.SortByHeaderAsync(e);
 
         private async void PreviousButton_Click(object sender, EventArgs e) =>
             await RunAsync(session.PreviousPageAsync);

OpenNest/Controls/DrawingSetBrowser.cs

@@ -242,9 +242,8 @@ namespace OpenNest.Controls
 
         private async void SetGrid_ColumnHeaderMouseClick(object sender, DataGridViewCellMouseEventArgs e)
         {
-            // Sorting a page locally would misrepresent the list; the server sorts all matches.
-            if (session != null && e.Button == MouseButtons.Left && setGrid.Columns[e.ColumnIndex].Tag is DrawingSetSortField field)
-                await RunAsync(() => session.SortByAsync(field));
+            if (session != null)
+                await pager.SortByHeaderAsync(e);
         }
 
         private async void PreviousButton_Click(object sender, EventArgs e) =>

OpenNest/Forms/AddReleaseDrawingsForm.cs

@@ -72,12 +72,9 @@ namespace OpenNest.Forms
             await RunLibraryAsync(() => librarySession.SetSearchAsync(searchBox.Text));
         }
 
-        private async void LibraryGrid_ColumnHeaderMouseClick(object sender, DataGridViewCellMouseEventArgs e)
-        {
-            // Sorting a page locally would misrepresent the library; the server sorts all matches.
-            if (e.Button == MouseButtons.Left && libraryGrid.Columns[e.ColumnIndex].Tag is DrawingSortField field)
-                await RunLibraryAsync(() => librarySession.SortByAsync(field));
-        }
+        private async void LibraryGrid_ColumnHeaderMouseClick(
+            object sender, DataGridViewCellMouseEventArgs e) =>
+            await libraryPager.SortByHeaderAsync(e);
 
         private async void PreviousButton_Click(object sender, EventArgs e) =>
             await RunLibraryAsync(librarySession.PreviousPageAsync);

OpenNest/Forms/EditDrawingSetForm.cs

@@ -171,12 +171,9 @@ namespace OpenNest.Forms
             await RunLibraryAsync(() => librarySession.SetSearchAsync(searchBox.Text));
         }
 
-        private async void LibraryGrid_ColumnHeaderMouseClick(object sender, DataGridViewCellMouseEventArgs e)
-        {
-            // Sorting a page locally would misrepresent the library; the server sorts all matches.
-            if (e.Button == MouseButtons.Left && libraryGrid.Columns[e.ColumnIndex].Tag is DrawingSortField field)
-                await RunLibraryAsync(() => librarySession.SortByAsync(field));
-        }
+        private async void LibraryGrid_ColumnHeaderMouseClick(
+            object sender, DataGridViewCellMouseEventArgs e) =>
+            await libraryPager.SortByHeaderAsync(e);
 
         private async void PreviousButton_Click(object sender, EventArgs e) =>
             await RunLibraryAsync(librarySession.PreviousPageAsync);

OpenNest/Forms/SavedNestsForm.cs

@@ -128,12 +128,7 @@ public sealed class SavedNestsForm : Form
             Visible = false,
             SortMode = DataGridViewColumnSortMode.NotSortable,
         });
-        // Sorting a page locally would misrepresent the archive; the server sorts all matches.
-        nestGrid.ColumnHeaderMouseClick += async (_, e) =>
-        {
-            if (e.Button == MouseButtons.Left && nestGrid.Columns[e.ColumnIndex].Tag is NestSortField field)
-                await RunAsync(() => session.SortByAsync(field));
-        };
+        nestGrid.ColumnHeaderMouseClick += async (_, e) => await pager.SortByHeaderAsync(e);
         nestGrid.CellDoubleClick += (_, e) =>
         {
             if (e.RowIndex >= 0)