Repaint the phone's chrome, radii and accent to the v5 vocabulary

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

@@ -29,7 +29,9 @@
     of "edit these six". The three that stay are the ones a count makes better rather than worse.
   -->
 
-  <Border Background="{StaticResource Chrome}" BorderBrush="{StaticResource Border}"
+  <!-- DeepChrome rather than Chrome, since v5: this bar takes the vault header's own place, so it takes
+       the vault header's own surface too — see the remark on that header in PhoneShell.axaml. -->
+  <Border Background="{StaticResource DeepChrome}" BorderBrush="{StaticResource Border}"
           BorderThickness="0,0,0,1" Padding="6,0" Height="56">
     <Grid ColumnDefinitions="Auto,*,Auto,Auto">