fix(ui): keep the database Open dialog on screen on a second monitor

The saved-nest browser opened maximized with MaximizedBounds set from the
owner screen's working area in absolute coordinates. Windows reads that
position relative to the monitor, so on a secondary screen the offset was
applied twice and the modal dialog was placed off-screen, leaving the
disabled main window with no way back to it.

Open it instead as a normal window sized to 90% of the owner screen's
working area and centered there; it still clears the taskbar and moves
between monitors like any other window.

OpenNest.WinForms.Tests/Forms/SavedNestsFormTests.cs

@@ -121,6 +121,30 @@ public class SavedNestsFormTests
             "The saved-nest dialog test did not complete.");
     }
 
+    [Fact]
+    public void OpensAsALargeNormalWindowInsideTheOwnersScreen()
+    {
+        StaTestThread.Run(
+            () =>
+            {
+                using var owner = new Form { StartPosition = FormStartPosition.Manual, Bounds = new(40, 40, 400, 300) };
+                owner.Show();
+                using var form = new SavedNestsForm(new FakeRepository());
+                form.Show(owner);
+                var area = Screen.FromControl(owner).WorkingArea;
+
+                // A maximized dialog with fixed MaximizedBounds landed off-screen on a secondary
+                // monitor, hiding the modal dialog behind a disabled main window.
+                Assert.Equal(FormWindowState.Normal, form.WindowState);
+                Assert.True(area.Contains(form.Bounds), $"Dialog bounds {form.Bounds} are outside the working area {area}.");
+                Assert.True(
+                    form.Width >= area.Width * 8 / 10 && form.Height >= area.Height * 8 / 10,
+                    $"Dialog size {form.Size} is small for the working area {area}.");
+            },
+            TestTimeout,
+            "The saved-nest dialog test did not complete.");
+    }
+
     private static NestRecord Record(string name) =>
         new() { Id = Guid.NewGuid(), Name = name, SavedAt = DateTime.Now };
 

OpenNest/Forms/SavedNestsForm.cs

@@ -69,10 +69,10 @@ public sealed class SavedNestsForm : Form
         details = new NestDetailsSession(LoadDetailsAsync);
 
         Text = WindowTitle;
-        StartPosition = FormStartPosition.CenterParent;
+        // Placed on the owner's screen in Load; see FitToScreen.
+        StartPosition = FormStartPosition.Manual;
         ClientSize = new Size(1280, 800);
         MinimumSize = new Size(800, 560);
-        WindowState = FormWindowState.Maximized;
         MinimizeBox = false;
         ShowInTaskbar = false;
 
@@ -278,9 +278,7 @@ public sealed class SavedNestsForm : Form
 
         Load += (_, _) =>
         {
-            // Keep a maximized dialog's bottom row clear of the taskbar.
-            var area = Screen.FromControl(Owner ?? this).WorkingArea;
-            MaximizedBounds = new Rectangle(area.Left, area.Top, area.Width, area.Height - 20);
+            FitToScreen();
 
             // Minimum sizes are applied once the container has its real height; setting them
             // on the default-sized container throws.
@@ -320,6 +318,25 @@ public sealed class SavedNestsForm : Form
         return base.ProcessCmdKey(ref msg, keyData);
     }
 
+    /// <summary>
+    /// Opens the dialog as a large normal window centered in the working area of the owner's
+    /// screen, so its bottom row stays clear of the taskbar. It is deliberately not maximized
+    /// with fixed <see cref="Form.MaximizedBounds"/>: Windows reads those relative to the
+    /// monitor, so bounds taken from a secondary screen moved the modal dialog off-screen there
+    /// and left the main window unusable.
+    /// </summary>
+    private void FitToScreen()
+    {
+        var area = Screen.FromControl(Owner ?? this).WorkingArea;
+        var width = System.Math.Max(MinimumSize.Width, area.Width * 9 / 10);
+        var height = System.Math.Max(MinimumSize.Height, area.Height * 9 / 10);
+        Bounds = new Rectangle(
+            System.Math.Max(area.Left, area.Left + (area.Width - width) / 2),
+            System.Math.Max(area.Top, area.Top + (area.Height - height) / 2),
+            width,
+            height);
+    }
+
     private static DataGridView CreateGrid()
     {
         var grid = new DataGridView