fix(reorder): save layer list AND preview layout immediately at drop; recording save dialog +10% (276→304)

Reorder: OnSceneElementsReordered now calls SaveLayoutNow() (was debounced
ScheduleSave) so a drag-drop persists instantly — one write stores the new
layer list (Source.SortOrder) and each layer's preview geometry (X/Y/W/H) in
the same rows. Reference: WPF ListBox drag-reorder requires an explicit persist
at drop; a debounce window lets a crash lose the drop.

Recording save dialog (RenameRecordingDialog.xaml): height 276→304 so the
Cancel/Save button row is no longer obscured; Save button named
SaveRecordingButton so the sizing test can assert it sits inside the client area.

Tests: deterministic seam test now asserts the dragged layer's geometry (preview
layout) is persisted with the new order; sizing test asserts 304 + textbox and
button-row bottoms within client area. 308/308 green.

ytLive.Tests/LayerReorderPersistenceTests.cs

@@ -21,7 +21,8 @@ namespace ytLive.Tests;
 /// directly (RemoveAt/Insert), bypassing SceneGraph's mutation surface, so the
 /// drop must be trapped as a data change and persisted. Real-App + temp-DB
 /// pattern (see WebcamOutputKeyTests); reuses the exact code-behind mutation and
-/// asserts the new order is written to the DB after the debounced background save.
+/// asserts the new order AND each layer's geometry (preview layout) are written
+/// to the DB — immediately at drop, no debounce window.
 /// </summary>
 [Collection("RealApp")]
 public sealed class LayerReorderPersistenceTests
@@ -97,8 +98,14 @@ public sealed class LayerReorderPersistenceTests
 
             Assert.True(PumpUntil(() => SourceNamesInDb(tempDb).SequenceEqual(expected),
                     TimeSpan.FromSeconds(10)),
-                "a real mouse drag-and-drop must be persisted by the debounced background save");
+                "a real mouse drag-and-drop must be persisted by the background save");
             Assert.Equal(expected, SourceNamesInDb(tempDb));
+
+            // The same drop must persist the PREVIEW LAYOUT too — each layer's
+            // geometry (X/Y/W/H) rides in the same Source rows as the SortOrder.
+            var dragged = vm.StagedScene.Elements.OfType<Source>().Single(s => s.Name == "ImgC");
+            Assert.Equal((dragged.X, dragged.Y, dragged.Width, dragged.Height),
+                GeometryInDb(tempDb, "ImgC"));
         }
         finally
         {
@@ -173,8 +180,15 @@ public sealed class LayerReorderPersistenceTests
 
             Assert.True(PumpUntil(() => SourceNamesInDb(tempDb).SequenceEqual(expected),
                     TimeSpan.FromSeconds(10)),
-                "the drag reorder must be persisted by the debounced background save");
+                "the drag reorder must be persisted at drop (immediate save)");
             Assert.Equal(expected, SourceNamesInDb(tempDb));
+
+            // The drop must persist the dragged layer's PREVIEW LAYOUT too — its
+            // X/Y/W/H ride in the same Source row, so one immediate save covers
+            // both the new layer list and the preview geometry.
+            var draggedSource = vm.StagedScene.Elements.OfType<Source>().Single(s => s.Name == dragged.Name);
+            Assert.Equal((draggedSource.X, draggedSource.Y, draggedSource.Width, draggedSource.Height),
+                GeometryInDb(tempDb, dragged.Name));
         }
         finally
         {
@@ -221,11 +235,31 @@ public sealed class LayerReorderPersistenceTests
         }
         catch (SqliteException)
         {
-            // The debounced save may hold the write lock mid-transaction — not yet.
+            // The save may hold the write lock mid-transaction — not yet.
             return [];
         }
     }
 
+    private static (double X, double Y, double Width, double Height) GeometryInDb(string path, string name)
+    {
+        try
+        {
+            using var connection = new SqliteConnection($"Data Source={path}");
+            connection.Open();
+            using var cmd = connection.CreateCommand();
+            cmd.CommandText = "SELECT X, Y, Width, Height FROM Source WHERE SceneId = 'scene-live' AND Name = $name;";
+            cmd.Parameters.AddWithValue("$name", name);
+            using var reader = cmd.ExecuteReader();
+            reader.Read();
+            return (reader.GetDouble(0), reader.GetDouble(1), reader.GetDouble(2), reader.GetDouble(3));
+        }
+        catch (SqliteException)
+        {
+            // The save may hold the write lock mid-transaction — not yet.
+            return (double.NaN, double.NaN, double.NaN, double.NaN);
+        }
+    }
+
     private static void SeedThreeLayers(string path)
     {
         using var connection = new SqliteConnection($"Data Source={path}");

ytLive.Tests/RenameRecordingDialogSizingTests.cs

@@ -4,10 +4,12 @@ using Xunit;
 namespace ytLive.Tests;
 
 /// <summary>
-/// The Rename Recording modal (creator-reported, 2026-09-18) cut off the file-name
-/// textbox: the fixed window was too short for its stacked content. The height is
-/// bumped 20% (230 → 276); this test renders the real dialog and asserts the textbox
-/// bottom edge lands inside the client area instead of clipping.
+/// The Rename Recording modal (the creator-reported dialog shown when a recording
+/// is ended, so it can be saved under a readable name) cut off its file-name textbox
+/// — and once the height was bumped 20% the Cancel/Save button row was revealed as
+/// previously obscured too. Height raised 230 → 304 (+20% then another +10%); this
+/// test renders the real dialog and asserts the textbox bottom edge AND the button
+/// row sit inside the client area instead of clipping.
 /// </summary>
 [Collection("RealApp")]
 public sealed class RenameRecordingDialogSizingTests
@@ -17,7 +19,7 @@ public sealed class RenameRecordingDialogSizingTests
     public RenameRecordingDialogSizingTests(RealAppHost app) => _app = app;
 
     [Fact]
-    public void DialogHeight_Bumps20Percent_AndNameBoxIsNotClipped()
+    public void DialogHeight_CoversTextboxAndButtonRow_WithoutClipping()
     {
         _app.Run(Run);
     }
@@ -27,7 +29,7 @@ public sealed class RenameRecordingDialogSizingTests
         var dialog = new RenameRecordingDialog("rec-2026-09-18");
         try
         {
-            Assert.Equal(276, dialog.Height);
+            Assert.Equal(304, dialog.Height);
 
             dialog.Show();
             dialog.UpdateLayout();
@@ -35,11 +37,18 @@ public sealed class RenameRecordingDialogSizingTests
             var box = dialog.NameBox;
             Assert.True(box.ActualWidth > 0, "file-name textbox must have a real layout");
             var client = (FrameworkElement)dialog.Content;
-            var bottom = box.TransformToAncestor(client)
+            var boxBottom = box.TransformToAncestor(client)
                 .TransformBounds(new Rect(box.RenderSize)).Bottom;
-            Assert.True(bottom <= client.ActualHeight,
-                $"textbox bottom ({bottom:0.##}) must sit inside the client area " +
+            Assert.True(boxBottom <= client.ActualHeight,
+                $"textbox bottom ({boxBottom:0.##}) must sit inside the client area " +
                 $"({client.ActualHeight:0.##}) — the dialog is clipping the name box");
+
+            var save = (FrameworkElement)client.FindName("SaveRecordingButton")!;
+            var saveBottom = save.TransformToAncestor(client)
+                .TransformBounds(new Rect(save.RenderSize)).Bottom;
+            Assert.True(saveBottom <= client.ActualHeight,
+                $"Save button bottom ({saveBottom:0.##}) must sit inside the client area " +
+                $"({client.ActualHeight:0.##}) — the button row is obscured");
         }
         finally
         {