Merge main into the phone connections branch

Main had already taken this branch's first two commits, so what merged is the
Connections work against three things that landed beside it. Four of the six
conflicts were prose about arrangements both sides changed; two were real.

**The phone hub gained a Teams row while this branch was moving the keychain
onto it.** Both are additions to `IsMoreSurface` and both belong: teams because
the desktop reaches them from its rail and the phone through the hub, the
keychain because a bottom bar is for the places a session moves between. The
membership test, the back gesture's first case and the hub's own arithmetic all
take the union. The distinction is now written down rather than implied — teams
is the design's count plus one, and the keychain is the only rearrangement of
it: the bar lost a slot to gain that row.

**`ConnectAndAnnounceAsync` was the real one.** Main gave it
`RememberTypedPasswordAsync`, which binds the password that just worked to the
host it worked on; this branch had replaced the `HostRowViewModel` that method
needs with a four-field `ConnectionTarget`. Keeping both meant deciding what a
manual connection does with a password that succeeded, and the answer was
already written on the screen it is typed into: nothing. There is no item to
bind a credential to and none to bind it on, and that path saves nothing by
design.

So `ConnectionTarget` carries the row again — as a nullable, in place of the
host id it had, with `HostId` derived from it. Two things read it and both are
things that can only be done to a keychain item rather than to an address:
naming the log entry, and keeping the password. Null is not missing data there;
it is the whole of what makes the manual path different, and having one field
rather than two keeps "was this a keychain host" a question with one answer.

The desktop's rail lost SFTP and S3 to the tab strip on main, so the README's
"a rail with nine slots has room" was true when it was written this afternoon
and is not now. It says the room rather than the number.

Phase 11's four new device checks and main's Phase 12 on teams were the same
conflict twice — two appends to the end of one file — and both are kept.

Verified after resolving: the solution builds, the Android head builds clean,
and 837 tests pass across the seven client suites, including main's own additions
(233 shell, 79 layout, 240 domain, 118 sync, 54 session, 74 terminal, 39
storage).

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

@@ -8,18 +8,22 @@
   <!--
     Design v2 — SETTINGS: the hub for everything the bottom bar has no room for.
 
-    Three slots and nine destinations is the arithmetic the design solves by putting the rest one tap
+    Three slots and ten destinations is the arithmetic the design solves by putting seven of them one tap
     deeper. This screen is that tap. It takes the shell as its data context rather than the vault, because
     every row on it is a navigation command and nothing here reads an item.
 
+    Teams is the tenth and the design never drew it — see the row itself. That one is the design's count
+    plus one rather than a rearrangement of it. The keychain below is a rearrangement, and the only one:
+    the bottom bar lost a slot to gain this row.
+
     The rows are the design's list rows rather than cards: a card is one thing you act on, and a destination
     is not a thing — it is a place. Each carries a sentence saying what is behind it, because a hub whose
     entries are one word each is a menu you have to open to read.
 
     ── from MORE to SETTINGS ──────────────────────────────────────────────────────────────────────────────
-    The hub was called More because that was the honest name for five things that did not fit. With the
-    keychain on it as well it is the place everything that is not connecting to a machine lives, which has a
-    name of its own and a glyph everyone already knows.
+    The hub was called More because that was the honest name for a handful of things that did not fit. With
+    the keychain on it as well it is the place everything that is not connecting to a machine lives, which
+    has a name of its own and a glyph everyone already knows.
 
     The keychain is first, and above the rule, because it is the only row here that holds the user's own
     material rather than a screen about the application. Everything below it is somewhere to look at what
@@ -123,6 +127,29 @@
           </Grid>
         </Button>
 
+        <!--
+          Teams, which the v2 design has no row for — it is a shipped screen the design had no slot for
+          rather than a drawn one with nothing behind it. It is on the phone because an invitation is
+          claimed by signing in, and somebody being invited is at least as likely to be holding a phone.
+
+          ◎ rather than a glyph of its own. The desktop rail already draws teams with it, and two heads
+          giving one destination two marks is how a user learns the wrong one.
+        -->
+        <Button Classes="row" Command="{Binding ShowScreenCommand}"
+                CommandParameter="{x:Static vm:ShellScreen.Team}">
+          <Grid ColumnDefinitions="Auto,*,Auto">
+            <TextBlock Grid.Column="0" Text="◎" Foreground="{StaticResource AccentText}" FontSize="14"
+                       Width="22" VerticalAlignment="Center" />
+            <StackPanel Grid.Column="1" Spacing="2" VerticalAlignment="Center">
+              <TextBlock Classes="mono" FontSize="13.5" FontWeight="SemiBold" Text="Teams" />
+              <TextBlock Classes="detail" Foreground="{StaticResource TextDim}"
+                         Text="Who shares a keychain with you, and who holds its key." />
+            </StackPanel>
+            <TextBlock Grid.Column="2" Text="›" Foreground="{StaticResource TextGhost}" FontSize="15"
+                       VerticalAlignment="Center" />
+          </Grid>
+        </Button>
+
         <Button Classes="row" Command="{Binding ShowScreenCommand}"
                 CommandParameter="{x:Static vm:ShellScreen.Preferences}">
           <Grid ColumnDefinitions="Auto,*,Auto">