Improve file operations, layout memory, and drive status.

Add a sequential file-operations queue with pause, reorder, and optional auto-clear; persist window size and tree width; show free space; and clear leftover indexing status.

Co-authored-by: Cursor <cursoragent@cursor.com>

src/Explorer.Presentation/ViewModels/NavigationTreeViewModel.cs

@@ -15,6 +15,7 @@ public sealed partial class NavNodeViewModel : ObservableObject
     [ObservableProperty] private string _status = "";
     [ObservableProperty] private bool _isOffline;
     [ObservableProperty] private bool _childrenLoaded;
+    [ObservableProperty] private bool _isDropTarget;
 
     public ObservableCollection<NavNodeViewModel> Children { get; } = [];
     public string Glyph { get; init; } = "\uE8B7";
@@ -321,6 +322,37 @@ public sealed class NavigationTreeViewModel
         }
     }
 
+    public async Task ApplySourceStateAsync(long sourceId, CancellationToken cancellationToken = default)
+    {
+        var source = await _sources.GetAsync(sourceId, cancellationToken).ConfigureAwait(true);
+        if (source is null)
+        {
+            return;
+        }
+
+        var node = FindBySourceId(Roots, sourceId)
+                   ?? (source.LastRootPath is null ? null : FindByPath(Roots, source.LastRootPath));
+        if (node is null)
+        {
+            return;
+        }
+
+        node.Status = FormatStatus(source);
+        node.IsOffline = source.Status == SourceStatus.Offline;
+    }
+
+    public static string FormatStatus(Source source)
+        => source.Status switch
+        {
+            SourceStatus.Offline => source.LastSeenUtc is null
+                ? "Offline"
+                : $"Offline · Last seen {source.LastSeenUtc.Value.ToLocalTime():d}",
+            SourceStatus.Scanning => "Indexing",
+            SourceStatus.Stale => "May be out of date",
+            SourceStatus.Error => "Error",
+            _ => source.IsIndexed ? "Indexed" : ""
+        };
+
     public static bool PathsEqual(string a, string b)
     {
         if (string.Equals(a, b, StringComparison.OrdinalIgnoreCase))
@@ -362,16 +394,7 @@ public sealed class NavigationTreeViewModel
         {
             Label = source.DisplayName,
             Path = source.LastRootPath ?? source.DisplayName,
-            Status = source.Status switch
-            {
-                SourceStatus.Offline => source.LastSeenUtc is null
-                    ? "Offline"
-                    : $"Offline · Last seen {source.LastSeenUtc.Value.ToLocalTime():d}",
-                SourceStatus.Scanning => "Indexing",
-                SourceStatus.Stale => "May be out of date",
-                SourceStatus.Error => "Error",
-                _ => source.IsIndexed ? "Indexed" : ""
-            },
+            Status = FormatStatus(source),
             IsOffline = source.Status == SourceStatus.Offline,
             Glyph = source.Kind == SourceKind.Removable ? "\uE88E" : source.Kind.IsNetwork() ? "\uE968" : "\uEDA2",
             SourceId = source.Id,
@@ -489,6 +512,30 @@ public sealed class NavigationTreeViewModel
         return null;
     }
 
+    private static NavNodeViewModel? FindBySourceId(IEnumerable<NavNodeViewModel> nodes, long sourceId)
+    {
+        foreach (var node in nodes)
+        {
+            if (node.IsPlaceholder)
+            {
+                continue;
+            }
+
+            if (node.SourceId == sourceId)
+            {
+                return node;
+            }
+
+            var child = FindBySourceId(node.Children, sourceId);
+            if (child is not null)
+            {
+                return child;
+            }
+        }
+
+        return null;
+    }
+
     private static NavNodeViewModel? FindByPath(IEnumerable<NavNodeViewModel> nodes, string path)
     {
         foreach (var node in nodes)