Give the application a settings area built from what really exists

src/DodoSSH.Client.Shell/ViewModels/VaultViewModel.cs

@@ -123,6 +123,9 @@ internal sealed class HostGroupRowViewModel(VaultGroupItem group, int hostCount)
 
     /// <summary>What the row says under the name.</summary>
     internal string Description => hostCount == 1 ? "1 host" : $"{hostCount} hosts";
+
+    /// <summary>The single letter the settings page's card draws on this group's tile.</summary>
+    internal string Initial => Label.Length > 0 ? Label[..1].ToUpperInvariant() : "?";
 }
 
 /// <summary>An entry in the host editor's group picker.</summary>
@@ -4667,8 +4670,20 @@ internal sealed partial class VaultViewModel(
         }
 
         SelectedTag = Tags.FirstOrDefault(row => row.EntityId == selectedId);
+
+        OnPropertyChanged(nameof(HasTagItems));
     }
 
+    /// <summary>
+    /// Whether there is at least one tag to manage.
+    /// </summary>
+    /// <remarks>
+    /// v5c-2: the settings Tags page's empty state. Named apart from <c>HostRowViewModel.HasTags</c>, which
+    /// answers a different question — whether one host wears any — rather than reusing that name at this
+    /// level and relying on which <c>x:DataType</c> a binding happens to be inside to tell the two apart.
+    /// </remarks>
+    internal bool HasTagItems => Tags.Count > 0;
+
     /// <summary>
     /// A host with its group chain applied: the port to dial, the user to log in as, and how to
     /// authenticate.
@@ -4763,6 +4778,28 @@ internal sealed partial class VaultViewModel(
         GroupFilter = Groups.FirstOrDefault(row => row.EntityId == filteredId);
 
         OnPropertyChanged(nameof(HasGroups));
+        OnPropertyChanged(nameof(UngroupedHostCount));
+    }
+
+    /// <summary>
+    /// How many hosts, across every shown vault, carry no group that still exists.
+    /// </summary>
+    /// <remarks>
+    /// v5c: the settings Groups page's "No group" footer row. The same dangling-reference reading
+    /// <see cref="FlattenIntoSections"/> gives the sidebar's own UNGROUPED heading — a host naming a group
+    /// this vault no longer has counts as ungrouped rather than vanishing — but counted over every shown
+    /// vault's hosts rather than over a find-box-filtered subset, because a settings page has no find box
+    /// and a count that shrank while somebody typed in one would be answering the wrong question.
+    /// </remarks>
+    internal int UngroupedHostCount
+    {
+        get
+        {
+            var known = Groups.Select(group => group.EntityId).ToHashSet();
+
+            return Hosts.Count(row =>
+                IsVaultShown(row.VaultId) && (row.Host.GroupId is not { } id || !known.Contains(id)));
+        }
     }
 
     /// <summary>
@@ -9881,6 +9918,35 @@ internal sealed partial class VaultViewModel(
         Status = $"Renaming {row.Label}.";
     }
 
+    /// <summary>
+    /// Opens the tag editor for a specific row, from the settings page's per-row edit icon.
+    /// </summary>
+    /// <remarks>
+    /// A thin wrapper around <see cref="EditTag"/> rather than a second implementation of what it does. The
+    /// keychain screen's own table drives <see cref="EditTag"/> off a <c>ListBox</c> selection; the settings
+    /// page draws one card per tag with no such selection to lean on, so this puts the row on
+    /// <see cref="SelectedTag"/> first and then asks the command that already knows how to open it — the
+    /// same trick <see cref="EditGroupFromHeading"/> plays for a group, except that command took the row as
+    /// an argument from the start and this one did not, because nothing needed it to until now.
+    /// </remarks>
+    /// <param name="row">The tag to edit.</param>
+    [RelayCommand]
+    private void EditTagRow(TagRowViewModel? row)
+    {
+        SelectedTag = row;
+        EditTagCommand.Execute(null);
+    }
+
+    /// <summary>Arms the delete confirmation for a specific row, from the settings page's per-row delete icon.</summary>
+    /// <inheritdoc cref="EditTagRow" path="/remarks" />
+    /// <param name="row">The tag to ask about deleting.</param>
+    [RelayCommand]
+    private void DeleteTagRow(TagRowViewModel? row)
+    {
+        SelectedTag = row;
+        DeleteTagCommand.Execute(null);
+    }
+
     /// <summary>Abandons the tag editor.</summary>
     [RelayCommand]
     private void CancelTagEdit()
@@ -10341,6 +10407,35 @@ internal sealed partial class VaultViewModel(
         await AutoSyncAsync(cancellationToken).ConfigureAwait(true);
     }
 
+    /// <summary>
+    /// Puts the selected pin's fingerprint on the clipboard.
+    /// </summary>
+    /// <remarks>
+    /// The twin of <see cref="CopyPublicKeyAsync"/> and the opposite call about secrecy: a host key
+    /// fingerprint is not one. Operators publish theirs on purpose, and the whole workflow this screen exists
+    /// for is comparing a pinned one against what was published — which is a copy-and-paste somebody should
+    /// not have to retype by hand out of a box that refuses to trim it.
+    /// </remarks>
+    [RelayCommand]
+    private async Task CopyPinFingerprintAsync()
+    {
+        if (SelectedKnownHost is not { } row)
+        {
+            Status = "Choose a pinned key first.";
+            return;
+        }
+
+        if (copyToClipboard is null)
+        {
+            Status = "This machine has no clipboard.";
+            return;
+        }
+
+        await copyToClipboard(row.Fingerprint).ConfigureAwait(true);
+
+        Status = $"Copied the fingerprint for {row.Host}.";
+    }
+
     /// <summary>
     /// Opens a terminal on the selected host.
     /// </summary>