Post the terminal's focus return past the dispatch that steals it

The first fix handed Android's focus back from inside the keys' Click
handlers — which fire inside the UP event's dispatch, and Avalonia's
own view requests focus for itself after every handled touch dispatch
returns (AvaloniaView.DispatchTouchEvent, decompiled from 12.1.1). So
the platform's request ran after ours and undid it microseconds later,
which is exactly what the phone showed: the terminal still lost focus.

The return is now posted onto the main looper, landing one message
after the dispatch that stole, and it is wired at the row for both
halves of a press — DOWN steals too, and Click only exists for UP, so
a keyboard detached at DOWN would otherwise stay detached for the whole
length of the press. Check 11.10a now also says what a tolerable blink
looks like against a failure that stays.

src/DodoSSH.Client.Android/Platform/TerminalFocus.cs

@@ -10,17 +10,24 @@ namespace DodoSSH.Client.Android.Platform;
 /// <b>The sibling of <see cref="SoftKeyboard"/>, and it exists for the same reason that one does:</b> the
 /// keyboard over a terminal belongs to the WebView's own native view, which Avalonia's focus manager does
 /// not own. The accessory row's keys are already <c>Focusable=false</c> — see TerminalScreen — so Avalonia's
-/// idea of focus never leaves the terminal when one is tapped. What still moves is <em>Android's</em>: the
-/// tap lands on Avalonia's own input view, which is focusable-in-touch-mode because Avalonia's text boxes
-/// need it to be, and the platform hands that view focus on the way to delivering the touch. The WebView's
-/// input connection dies with its focus, the keyboard swaps to the layout it shows an editor that takes no
-/// text, and the inset churn that follows can leave it sitting on top of the very row that was tapped.
+/// idea of focus never leaves the terminal when one is tapped. What still moves is <em>Android's</em>:
+/// <c>AvaloniaView.DispatchTouchEvent</c> (decompiled from Avalonia.Android 12.1.1) ends every handled
+/// touch — DOWN and UP alike — with a <c>RequestFocus()</c> for Avalonia's own view. The WebView's input
+/// connection dies with its focus, the keyboard swaps to the layout it shows an editor that takes no text,
+/// and the inset churn that follows can leave it sitting on top of the very row that was tapped.
 /// </para>
 /// <para>
-/// So each accessory key hands focus straight back once its byte is on the wire. The page inside the
-/// WebView never noticed anything — its own DOM focus never moved — so regaining native focus re-establishes
-/// the same input connection and the keyboard settles back to what it was. Skipped when the WebView is still
-/// focused, which makes the call free on any platform arrangement where the steal never happened.
+/// <b>Posted, not called — the posting is the fix's second attempt, and the first one's failure is why.</b>
+/// The first version called <c>RequestFocus()</c> from the keys' own Click handlers, which fire
+/// <em>inside</em> the UP event's dispatch — and the platform's own request runs <em>after</em> dispatch
+/// returns, so it undid ours a few microseconds later and the terminal stayed unfocused. A posted runnable
+/// runs on the next main-looper message, after the platform has taken its turn, so ours is the request that
+/// sticks. The focus check lives inside the posted runnable for the same reason: the answer at call time is
+/// about to be made stale by the very mechanism this exists to counter.
+/// </para>
+/// <para>
+/// The page inside the WebView never noticed any of this — its own DOM focus never moved — so regaining
+/// native focus re-establishes the same input connection and the keyboard settles back to what it was.
 /// </para>
 /// <para>
 /// Found by walking the decor view rather than asked of the <c>NativeWebView</c> control, because the
@@ -39,10 +46,18 @@ internal static class TerminalFocus
             return;
         }
 
-        if (FindWebView(decor) is { IsFocused: false } webView)
+        if (FindWebView(decor) is not { } webView)
         {
-            webView.RequestFocus();
+            return;
         }
+
+        webView.Post(() =>
+        {
+            if (!webView.IsFocused)
+            {
+                webView.RequestFocus();
+            }
+        });
     }
 
     private static View? FindWebView(ViewGroup parent)