feat(desktop): one Drawing Sets window with Sets and Releases tabs

The drawing sets window now has two tabs. Releases hosts the release list
(paging, nests, Undo Release, New Release) as a SetReleasesView control that
replaces SetReleasesForm. File > Releases stays as a shortcut that opens the
window on that tab. A set's Releases (Sets tab) and a library drawing's
Releases (Drawing Library) open the tab filtered to it, with the filter shown
above the list and Clear Filter to list every release. Releases re-reads its
page whenever the tab is shown again, so a release made on Sets appears.

The set editor gets History... for a saved set; the Sets tab keeps its
History button until the browser's buttons are rearranged.

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

OpenNest.Data/DrawingSetEditSession.cs

@@ -56,6 +56,9 @@ public sealed class DrawingSetEditSession
 
     public Guid Id { get; }
 
+    /// <summary>The store the set is read from and saved to; also reads its history.</summary>
+    public IDrawingSetStore Store => _sets;
+
     public string SavedBy { get; }
 
     /// <summary>The set as last read or saved; null until a new set is first saved.</summary>