Merge branch 'claude/groups-vault-sharing-e4b154'

# Conflicts:
#	src/DodoSSH.Client.Shell/ViewModels/VaultViewModel.cs

src/DodoSSH.Client.Android/Views/HostsScreen.axaml

@@ -125,7 +125,21 @@
         <DataTemplate DataType="vm:SidebarGroupHeader">
           <Grid ColumnDefinitions="Auto,*,Auto,Auto" Margin="8,12,8,5">
             <TextBlock Grid.Column="0" Classes="detail" Text="{Binding Chevron}" VerticalAlignment="Center" />
-            <TextBlock Grid.Column="1" Classes="section" Text="{Binding Label}" Margin="7,0,0,0" />
+
+            <!--
+              The name, and the vault it is in where this session holds more than one. The badge is what
+              makes one heading per group survive a shared vault: two vaults may each hold a "production",
+              and this list has no nesting to tell the two apart with. Drawn as the same outline tag a host
+              row wears, so "which vault" looks the same wherever it is answered.
+            -->
+            <StackPanel Grid.Column="1" Orientation="Horizontal" Spacing="6" Margin="7,0,0,0">
+              <TextBlock Classes="section" Text="{Binding Label}" TextTrimming="CharacterEllipsis" />
+              <Border Classes="tag outline" VerticalAlignment="Center"
+                      IsVisible="{Binding HasVaultBadge}">
+                <TextBlock Text="{Binding VaultBadge}" />
+              </Border>
+            </StackPanel>
+
             <TextBlock Grid.Column="2" Classes="detail" Text="{Binding Count}" FontSize="9"
                        VerticalAlignment="Center" />
 
@@ -369,6 +383,27 @@
 
           <TextBox Classes="field" Text="{Binding GroupEditorLabel}" PlaceholderText="group name" />
 
+          <!--
+            ◆ WHICH VAULT THIS GROUP WILL LIVE IN, on the same terms as the host editor's picker above and
+            for the same reason: it is what makes the group shared, and it cannot be changed afterwards.
+            Above INSIDE because it decides what INSIDE can offer — a parent belongs to one vault, and one
+            from another is a level half the readers cannot resolve.
+          -->
+          <StackPanel Spacing="6" IsVisible="{Binding ShowsGroupEditorVaultChoice}">
+            <TextBlock Classes="label" Text="VAULT" Margin="0,4,0,0" />
+            <ComboBox ItemsSource="{Binding GroupEditorVaultChoices}"
+                      SelectedItem="{Binding GroupEditorSelectedVault}"
+                      HorizontalAlignment="Stretch" MinHeight="44">
+              <ComboBox.ItemTemplate>
+                <DataTemplate x:DataType="vm:VaultChoiceViewModel">
+                  <TextBlock Classes="mono" FontSize="12" Text="{Binding Display}" />
+                </DataTemplate>
+              </ComboBox.ItemTemplate>
+            </ComboBox>
+            <TextBlock Classes="body"
+                       Text="A group in a shared vault is visible to everybody holding that vault's key, and only hosts in the same vault can be filed under it." />
+          </StackPanel>
+
           <TextBlock Classes="label" Text="INSIDE" Margin="0,4,0,0" />
           <ComboBox ItemsSource="{Binding GroupEditorParentChoices}"
                     SelectedItem="{Binding GroupEditorSelectedParent}"