Let the phone delete a host, and move or remove a group

The desktop gained three things the phone did not follow: moving a group to
another vault, the second question asking whether a group's deletion takes its
hosts with it, and — since long before either — deleting a host at all. What
that left was a head whose v3 + can fill a keychain and whose editors can
correct one, with no way to empty either.

The commands could not simply be bound. DeleteGroup and MoveGroup aim at
GroupTarget, which is the selected card or the open group, and the phone has
neither: its list draws headings, and a heading's selection deliberately bounces
back to the host. Called bare on that head they would have returned having done
nothing — a DELETE that appears to have been pressed and has not. Both now take
the row and fall back to GroupTarget for the desktop's menu, and
ConfirmMoveGroupAsync resolves from the panel's own movingGroupId rather than
from the selection, which is also the honester answer on the desktop: what moves
is the shelf the panel was opened on.

The heading's pencil became a menu. Three icons after a chevron, a name, a vault
badge and a count is what would be left of the name at 360dp, so the ⋯ raises
the add sheet's shape carrying Edit, Move to another vault, a rule, and Delete —
the desktop's card menu, in the one idiom this screen already has. It does not
carry Open: the desktop's grid holds one level of the group tree and this list
holds all of it flattened, so there is nowhere to open a group into.

DELETE under a host sits on a row of its own beneath EDIT and MOVE rather than
beside them. A phone has no hover and no tooltip, so where a thumb lands is the
only thing separating a destructive control from an ordinary one. Both questions
take the controls that asked them — ShowsConnectControls, which is the phone's
half of the rule ShowsHostPaneActions already carries for the desktop's drawer —
so DELETE cannot be pressed a second time underneath its own confirmation.

Preferences gained the running version, and the sentence saying this head does
not replace itself and that no DodoSSH server will ever offer one. It reads
Updates.CurrentVersion off the same view model the desktop's UPDATES section
does, over the null channel that reports itself unsupported.

Nothing was needed for the realtime push: it is composed in ServerConnection,
which both heads use.

Seven tests, all phone-shaped — a group acted on with nothing selected, the menu
waved away leaving nothing armed, the ungrouped heading raising none, and the
bar's three states. The rectangles remain unmeasurable for the reason phase 8
gives; the checks for them are 8.10 to 8.13 and 13.6.

src/DodoSSH.Client.Android/Views/PhoneShell.axaml.cs

@@ -370,8 +370,8 @@ internal sealed partial class PhoneShell : UserControl
     /// <returns>Whether anything was closed, and so whether back has been spent.</returns>
     /// <remarks>
     /// <para>
-    /// Order is the whole of it. The add sheet sits over the list and the two editors sit in place of it, so
-    /// the sheet has to go first — closing an editor while a sheet was open would leave the sheet floating
+    /// Order is the whole of it. The two sheets sit over the list and the two editors sit in place of it, so
+    /// a sheet has to go first — closing an editor while a sheet was open would leave the sheet floating
     /// over a list nobody asked to see, and the second back would then close the sheet rather than the
     /// editor the user was looking at.
     /// </para>
@@ -394,6 +394,16 @@ internal sealed partial class PhoneShell : UserControl
             return true;
         }
 
+        // The other sheet, and it is checked beside the first rather than after the editors for the same
+        // reason: it is raised over the list, so it is the nearest thing on screen. The two cannot be open
+        // at once — one is raised by the +, the other by a heading, and each hides the list the other's
+        // control is on — so their order between themselves decides nothing.
+        if (vault.GroupSheet is not null)
+        {
+            vault.CloseGroupSheetCommand.Execute(null);
+            return true;
+        }
+
         if (vault.IsEditing)
         {
             vault.CancelEditCommand.Execute(null);