Android: ask what to connect to on Connections, the same prompt the desktop's empty terminal draws

The phone's Connections screen with nothing open had a box that took an address alone, which left a
saved machine several screens away. It now draws the desktop's prompt over the same view-model state:
"connect to:" takes a saved host's name or user@host[:port], and a password line follows only when
one is needed. Names, addresses and refusals are read exactly as on the desktop, and nothing typed
here is saved.

What a phone changes: the hosts matching so far are thumb-sized buttons that take a host outright,
since there is no Tab; CONNECT is always drawn, since the IME's return key may only close the
keyboard; BACK, and the system back gesture, step off the password line rather than leaving the
screen; and the password's label sits on its own line. The keyboard follows the question onto the
password line, but is not raised when the screen opens, where it would cover the recent list.

Recent rows now go onto the prompt too. Covered by a new ShellFlowTests case for a tapped match on
top of the shared prompt cases; manual check 11.14.

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

@@ -345,9 +345,11 @@
         running this surface is where a connection is made rather than a page apologising for having
         nothing on it. Two things are offered, in the order somebody reaches for them.
 
-        A box, because the case this application had no answer for is the address somebody has just been
-        given. Everything else here starts from a keychain item, which is right for a machine used twice and
-        is several screens of work for one used once.
+        A prompt, because a terminal with nothing in it should do what a terminal does, which is ask — the
+        same one the desktop draws in its empty terminal, over the same view-model state. It takes a saved
+        host's name or user@host for a machine that is not saved, and asks for a password only when one is
+        needed. See ConnectPrompt.axaml. It replaced a box that took addresses alone, which left a saved
+        machine several screens away from here.
 
         And the machines already connected to, under it, because that is the commoner half by far: the
         thing most likely to be wanted is the thing that was wanted yesterday. They come out of the vault's
@@ -359,44 +361,7 @@
 
           <TextBlock Classes="title" FontSize="13" Text="CONNECT TO A MACHINE" />
 
-          <!--
-            The manual target. One box in the grammar people already have — user@host, or user@host:port —
-            rather than three, because three boxes on a phone is three taps between three keyboards for
-            something that arrives as one string.
-          -->
-          <TextBox Classes="field" Text="{Binding Vault.ManualTarget}"
-                   PlaceholderText="user@host or user@host:port">
-            <TextBox.KeyBindings>
-              <KeyBinding Gesture="Enter" Command="{Binding Vault.ConnectManuallyCommand}" />
-            </TextBox.KeyBindings>
-          </TextBox>
-
-          <!--
-            A typed password and nothing else. Offering the keychain's keys here would be a second binding
-            resolution beside the one the connect path already has, and a key is the reason to save the
-            machine as a host rather than dial it from a box.
-
-            Classes="secret" and not merely PasswordChar: the class is what also tells the software keyboard
-            this is not prose, which is the difference between dots on screen and dots on screen with the
-            password in the IME's dictionary. See Theme/Phone.axaml.
-          -->
-          <TextBox Classes="field secret" Text="{Binding Vault.ManualPassword}"
-                   PlaceholderText="password">
-            <TextBox.KeyBindings>
-              <KeyBinding Gesture="Enter" Command="{Binding Vault.ConnectManuallyCommand}" />
-            </TextBox.KeyBindings>
-          </TextBox>
-
-          <Button Classes="primary" Content="CONNECT" Command="{Binding Vault.ConnectManuallyCommand}" />
-
-          <!--
-            Beside the box rather than on the shell's status line. What fails here is about what was typed —
-            a missing account, a port that is not a number — and a sentence about a text box belongs under
-            the text box.
-          -->
-          <TextBlock Classes="detail" TextWrapping="Wrap" Foreground="{StaticResource WarnText}"
-                     Text="{Binding Vault.ManualStatus}"
-                     IsVisible="{Binding Vault.ManualStatus, Converter={x:Static StringConverters.IsNotNullOrEmpty}}" />
+          <views:ConnectPrompt />
 
           <TextBlock Classes="body"
                      Text="Nothing typed here is saved. A machine worth keeping belongs on HOSTS, where it can carry a key, a group's defaults and a name." />
@@ -410,14 +375,13 @@
               <ItemsControl.ItemTemplate>
                 <DataTemplate x:DataType="vm:ConnectionLogRowViewModel">
                   <!--
-                    Tapping one does not connect, and that is deliberate rather than a missing step. A row
-                    that names a keychain host goes to that host with its connect bar — which is where its
-                    key, or its password box, or its refusal lives — and one that names only an address goes
-                    back into the box above, without the password, which was never stored. Either way what
-                    happens next is visible before anything is dialled. See ConnectToRecentCommand.
+                    A tap goes onto the prompt above and carries on as if it had been typed: a keychain host
+                    connects, or asks for its password there; an address asks for its password, which was
+                    never stored. Nothing is dialled before the prompt has asked whatever it needs to. See
+                    MainWindowViewModel.ChoosePromptRecentCommand.
                   -->
                   <Button Classes="row" MinHeight="52" Padding="12,8" CornerRadius="10"
-                          Command="{Binding $parent[views:TerminalScreen].((vm:MainWindowViewModel)DataContext).ConnectToRecentCommand}"
+                          Command="{Binding $parent[views:TerminalScreen].((vm:MainWindowViewModel)DataContext).ChoosePromptRecentCommand}"
                           CommandParameter="{Binding}">
                     <Grid ColumnDefinitions="*,Auto">
                       <StackPanel Grid.Column="0" Spacing="2" VerticalAlignment="Center">