feat(blazor): reflect current folder hierarchy in the URL

src/Atypical.VirtualFileSystem.DemoBlazorApp/Components/Pages/Home.razor

@@ -186,14 +186,40 @@
 
     private bool HasItems => GetCurrentItems().Any();
 
+    // The current directory is reflected in the URL as ?path=docs/src so the
+    // location is deep-linkable (refresh / share / back-forward restore it).
+    [SupplyParameterFromQuery(Name = "path")]
+    public string? PathQuery { get; set; }
+
     protected override void OnInitialized()
     {
         StateService.OnDataChanged += RequestRender;
-        StateService.OnCurrentPathChanged += RequestRender;
+        StateService.OnCurrentPathChanged += OnCurrentPathChanged;
         StateService.OnSortChanged += RequestRender;
         StateService.OnViewModeChanged += RequestRender;
     }
 
+    // Runs on first render and whenever the query string changes (deep link,
+    // refresh, browser back/forward): make the current folder match the URL.
+    protected override void OnParametersSet()
+    {
+        var desired = VFSStateService.FromQueryPath(PathQuery);
+        if (StateService.CurrentPath != desired)
+            StateService.NavigateTo(desired);
+    }
+
+    // When navigation happens through state (breadcrumb, opening a folder,
+    // import, etc.) push the matching URL so the address bar stays in sync.
+    private void OnCurrentPathChanged()
+    {
+        var target = VFSStateService.ToFolderUrl(StateService.CurrentPath);
+        var current = "/" + Navigation.ToBaseRelativePath(Navigation.Uri);
+        if (!string.Equals(current, target, StringComparison.Ordinal))
+            Navigation.NavigateTo(target);
+
+        InvokeAsync(StateHasChanged);
+    }
+
     // Service events may fire on non-UI threads; marshal to the Dispatcher.
     private void RequestRender() => InvokeAsync(StateHasChanged);
 
@@ -483,7 +509,7 @@
     public void Dispose()
     {
         StateService.OnDataChanged -= RequestRender;
-        StateService.OnCurrentPathChanged -= RequestRender;
+        StateService.OnCurrentPathChanged -= OnCurrentPathChanged;
         StateService.OnSortChanged -= RequestRender;
         StateService.OnViewModeChanged -= RequestRender;
     }

src/Atypical.VirtualFileSystem.DemoBlazorApp/Components/Pages/Recent.razor

@@ -87,8 +87,7 @@
 
         if (entry.IsDirectory)
         {
-            StateService.NavigateTo(entry.Path);
-            Navigation.NavigateTo("/");
+            Navigation.NavigateTo(VFSStateService.ToFolderUrl(entry.Path));
         }
         else
         {

src/Atypical.VirtualFileSystem.DemoBlazorApp/Components/Pages/Search.razor

@@ -227,9 +227,8 @@
     {
         if (result.IsDirectory)
         {
-            StateService.NavigateTo(result.Path.Value);
             RecentFiles.RecordAccess(result.Path.Value, true);
-            Navigation.NavigateTo("/");
+            Navigation.NavigateTo(VFSStateService.ToFolderUrl(result.Path.Value));
         }
         else
         {

src/Atypical.VirtualFileSystem.DemoBlazorApp/Components/Pages/Starred.razor

@@ -93,8 +93,7 @@
 
         if (item.IsDirectory)
         {
-            StateService.NavigateTo(item.Path);
-            Navigation.NavigateTo("/");
+            Navigation.NavigateTo(VFSStateService.ToFolderUrl(item.Path));
         }
         else
         {

src/Atypical.VirtualFileSystem.DemoBlazorApp/Services/VFSStateService.cs

@@ -74,6 +74,42 @@ public string CurrentPath
         }
     }
 
+    /// <summary>The VFS root path scheme.</summary>
+    public const string RootPath = "vfs://";
+
+    /// <summary>
+    /// Builds the relative app URL that represents a directory, e.g.
+    /// "vfs://docs/src" -> "/?path=docs/src" (root -> "/"). Segments are
+    /// individually escaped so the hierarchy stays readable in the address bar.
+    /// </summary>
+    public static string ToFolderUrl(string? vfsPath)
+    {
+        var relative = StripScheme(vfsPath);
+        if (string.IsNullOrEmpty(relative))
+            return "/";
+
+        var escaped = string.Join("/", relative.Split('/').Select(Uri.EscapeDataString));
+        return $"/?path={escaped}";
+    }
+
+    /// <summary>
+    /// Converts a "path" query value back into a full VFS path, e.g.
+    /// "docs/src" -> "vfs://docs/src" (null/empty -> "vfs://").
+    /// </summary>
+    public static string FromQueryPath(string? queryPath)
+    {
+        var relative = (queryPath ?? string.Empty).Replace('\\', '/').Trim('/');
+        return string.IsNullOrEmpty(relative) ? RootPath : $"{RootPath}{relative}";
+    }
+
+    private static string StripScheme(string? vfsPath)
+    {
+        var value = vfsPath ?? string.Empty;
+        if (value.StartsWith(RootPath, StringComparison.Ordinal))
+            value = value[RootPath.Length..];
+        return value.Trim('/');
+    }
+
     // View preferences
     public ViewMode ViewMode
     {