feat(ui): Erststart-Banner und Textkette Repo→Task→Queue→Review (UX-Struktur C)

HasNoLinkedRepo on ListsIslandViewModel drives a dismiss-less banner under the
Lists-Island header when no User list has a linked repo; recomputed on load
and after list CRUD / list-settings save. Sharpens the #192 empty-state texts
into one readable chain (banner → no-repo list → repo-linked list) and adds a
line to the WorkConsole review gate spelling out that Approve also merges the
whole unit.

src/ClaudeDo.Ui/Views/Islands/Detail/WorkConsole.axaml

@@ -371,13 +371,16 @@
                       IsVisible="{Binding Merge.ShowMergeSection}" />
 
               <!-- Gate: you must open the diff before Approve & Merge unlocks. -->
-              <StackPanel Orientation="Horizontal" Spacing="6"
-                          IsVisible="{Binding ShowReviewDiffHint}">
-                <PathIcon Data="{StaticResource Icon.ArrowOut}" Width="11" Height="11"
-                          Foreground="{DynamicResource AmberBrush}" VerticalAlignment="Center" />
-                <TextBlock Classes="meta" VerticalAlignment="Center"
-                           Foreground="{DynamicResource AmberBrush}"
-                           Text="Open the diff to enable merge" />
+              <StackPanel Spacing="2" IsVisible="{Binding ShowReviewDiffHint}">
+                <StackPanel Orientation="Horizontal" Spacing="6">
+                  <PathIcon Data="{StaticResource Icon.ArrowOut}" Width="11" Height="11"
+                            Foreground="{DynamicResource AmberBrush}" VerticalAlignment="Center" />
+                  <TextBlock Classes="meta" VerticalAlignment="Center"
+                             Foreground="{DynamicResource AmberBrush}"
+                             Text="Open the diff to enable merge" />
+                </StackPanel>
+                <TextBlock Classes="meta" Margin="17,0,0,0"
+                           Text="{loc:Tr session.approveMergesUnitHint}" />
               </StackPanel>
 
               <!-- Gate: a unit merge is draining this task's subtasks, so Cancel is locked

src/ClaudeDo.Ui/Views/Islands/ListsIslandView.axaml

@@ -30,6 +30,24 @@
       </StackPanel>
     </Border>
 
+    <!-- ── No-repo banner — visible until any User list has a linked working dir; no
+         dismiss, no persisted state, comes back if the last repo link is removed. ── -->
+    <Border DockPanel.Dock="Top"
+            IsVisible="{Binding HasNoLinkedRepo}"
+            Margin="12,0,12,12"
+            Background="{DynamicResource DeepBrush}"
+            BorderBrush="{DynamicResource LineBrush}"
+            BorderThickness="1"
+            CornerRadius="6"
+            Padding="14,10">
+      <StackPanel Spacing="8">
+        <TextBlock Classes="body" Text="{loc:Tr lists.noRepoBannerText}" TextWrapping="Wrap"/>
+        <Button Classes="btn" HorizontalAlignment="Right"
+                Content="{loc:Tr lists.noRepoBannerButton}"
+                Command="{Binding OpenRepoImportCommand}"/>
+      </StackPanel>
+    </Border>
+
     <!-- ── Footer ── -->
     <Border DockPanel.Dock="Bottom"
             BorderBrush="{DynamicResource LineBrush}" BorderThickness="0,1,0,0"